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NORTH CAROLINA GEOLOGICAL SURVEY 



GEOLOGIC TIME SCALE FOR NORTH CAROLINA 



EON 


ERA 


PERIOD 


EPOCH 


GEOLOGIC EVENTS IN NORTH CAROLINA 


AGE* 


U 

M 

O 
S3 
O 

C6 

a 
z 

< 

X 


O 

o 

S3 
O 

z 

Ed 
U 


Quaternary 


Recent 


Deposition of sediments in Coastal Plain. 
Erosion of Piedmont and Appalachian 
Mountains to their present rugged features. 


1.7 i 


Pleistocene 


Tertiary 


Pliocene 


5 


Miocene 


Phosphate deposited in eastern North 
Carolina (Beaufort and Pamlico Counties). 


24 


Oligocene 


Limestone deposited in Coastal Plain. Weathering 
and erosion continue in Piedmont and Mountains. 


66 


Eocene 


.Paleocene 


u 
o 

S3 
O 

U 


•Cretaceous"H 


'Late 


Deposition of estuarine and marine sediments in 

the Coastal Plain. 

Continued erosion of the Piedmont and Mountains. 


138 


Early 


Sediments deposited in northern half of the 
Coastal Plain. Cape Fear Arch begins to develop. 
Piedmont and Mountains eroded. 


f ■ * ■ * 

Jurassic 


Late 


Marine sediments deposited on outer continental 

shelf. 

Piedmont and mountains eroded. 


205 


Middle 


Weathering and erosion of the Blue Ridge 

and the Piedmont areas. 

Emplacement of diabase dikes and sheets. 


Early 


Triassic 


Late 


Faulting and rifting creates Deep River, Dan River, 
and Davie basins. Basins fill with continental 
clastic sediments known as "red beds". 


240 


Middle 


Formation of the Atlantic Ocean as North 
America and Africa drifted apart. Weather- 
ing and erosion of Piedmont and Mountains. 


Early 


u 

o 

S3 

o 

w 
-J 
<! 
a. 


Permian 




Final collision of North America and Africa. Thrust 
faulting in west; deformation in eastern Piedmont. 


290 


Pennsylvai 


lian 


a 

s 

IH 

a 

w 

3 

o 
u 

e 

o 

a 
u 

E 
u 
o 

E 

n 


Time of uplift and erosion. 


330 


Mississi pp 


ian 


Time of uplift and erosion. 


360 


Devonian 




Emplacement of lithium, mica, and feldspar-rich 
pegmatites, primarily in the Kings Mountain and 
Spruce Pine districts. Metamorphism of Carolina 
slate belt. Period of erosion. 


410 


Silurian 




Period of uplift and erosion. 


435 


Ordovician 




Continental collision and beginning of mountain 
building process— faulting, folding, and 
metamorphism of pre-existing rocks. 


500 


Cambrian 




Sandstone, shale, and limestone deposited in the 
mountain area. Continued deposition of Carolina 
slate belt rocks. Gold deposits of the slate belt form 


570 


u 
o 

S3 

o 

w 

H 

o 

OS 

c 


Z 

< 

03 

u 

Ed 

ftS 
0. 


Late 




Sedimentary and volcanic rocks deposited in the 
mountains and Piedmont. Local intrusions of 
igneous rocks. 


900 


Middle 




Sedimentary, volcanic, and igneous rocks formed 
in the Blue Ridge and metamorphosed to gneisses 
and schists. 


1600 


Early 




Oldest dated rock in North Carolina is 1,800 
million years old. 


2500 




* Ei 
o 


>timated age in 
! years. 


millions 


Oldest known rock in U.S. is 3,600 million years. 
Oldest known rocks in world are 3,850 million years. 
Formation of the Earth was 4,500 million years ago. 





A GEOLOGIC GUIDE TO 



NORTH CAROLINA'S STATE PARKS 



BULLETIN 91 



N.C. DOCUMENTS 

CLEARINGHOUSE 

m ? 1959 



Edited by 
P. Albert Carpenter, HI 



N.C. STATE LIBRARY 
RALBGH 




NORTH CAROLINA GEOLOGICAL SURVEY SECTION 

DIVISION OF LAND RESOURCES 

DEPARTMENT OF NATURAL RESOURCES 

AND COMMUNITY DEVELOPMENT 



Raleigh 
1989 




North Carolina Geological Survey 



A Geologic Guide To North Carolina's State Parks 



Edited by P. Albert Carpenter, III 



CONTENTS 



Introduction 


1 


Weymouth Woods-William F. Wilson 


24 


General geology 


5 


Piedmont parks 


26 


Blue Ridge belt 


5 


Crowders Mountain-P. A. Carpenter, III 


27 


Inner Piedmont belt 


5 


Duke Power-P. Albert Carpenter, III 


29 


Kings Mountain belt 


5 


Eno River- William F. Wilson 


31 


Milton belt 


5 


Hanging Rock- William F. Wilson 


33 


Charlotte belt 


5 


Piedmont Reservoirs- 




Carolina slate belt 


5 


State Recreation Areas 


35 


Triassic basins 


5 


Falls Lake-Joann A. Carraway 


35 


Raleigh belt 


5 


B. Everette Jordan-P. A. Carpenter, III 


36 


Eastern slate belt 


5 


Kerr Lake- William F. Wilson 


36 


Coastal Plain 


6 


Medoc Mountain-Charles W. Hoffman 


38 


Geologic time scale 


6 


Morrow Mountain-P. Albert Carpenter, III 


41 


Coastal parks 


7 


Pilot Mountain-William F. Wilson 


44 


Carolina Beach and Fort Fisher 




Raven Rock-P. Albert Carpenter, III 


46 


Recreation Area-Patricia E. Gallagher 


8 


South Mountain-P. Albert Carpenter, III 


48 


Cliffs of the Neuse-Charles W. Hoffman 


10 


William B. Umstead-P. A. Carpenter, III 


50 


Barrier islands-Charles W. Hoffman 


12 


Mountain parks 


52 


Fort Macon-Charles W. Hoffman 


13 


Mount Jefferson-Carl E. Merschat 


53 


Hammocks Beach-Edward R. Burt, III 


15 


Mount Mitchell-P. Albert CarpenterJII 


55 


Jockey's Ridge-Charles W. Hoffman 


16 


New River-Carl E. Merschat 


57 


Merchants Millpond-Charles W. Hoffman 


18 


Stone Mountain-Carl E. Merschat 


59 


Carolina Bays-Patricia E. Gallagher 


20 


Other parks 


61 


Lake Waccamaw-Patricia E. Gallagher 


22 


Acknowledgements 


62 


Singletary Lake-Patricia E. Gallagher 


22 


Glossary 


63 


Jones Lake-Patricia E. Gallagher 


23 


Geologic time scale inside front cover 


Pettigrew-Charles W. Hoffman 


23 








A Geologic Guide To North Carolina's State Parks 



INTRODUCTION 



eology is something most of us do not think 
about as we go about our daily activities. 
Yet, all of us are affected by the powerful geologic 
processes that formed our continent — creating 
varied minerals and rocks; concentrating minerals 
into mineable ore deposits; eroding and sculpting 
landscape — eventually resulting in the beautiful 
State we enjoy today. 



North Carolina extends across three major 
physiographic provinces: the Coastal Plain, the 
Piedmont, and the Blue Ridge. These three prov- 
inces provide a diversity of landscapes and sea- 
scapes. They include the barrier islands and 
swampy areas on the Coast, the rolling Piedmont 
with its occasional prominent monadnocks, and 
the towering peaks of the Blue Ridge Mountains. 
Within the three physiographic provinces, the 
rocks are grouped into belts of similar rocks. The 
Blue Ridge Province includes the Blue Ridge belt; 
the Piedmont Province includes the Triassic ba- 
sins, the Inner Piedmont, Kings Mountain, Milton, 
Charlotte, Carolina slate, Raleigh, and Eastern 
slate belts; and the Coastal Plain Province includes 
rocks of the Coastal Plain and Sandhills area. 

The varied geology is reflected in the diver- 
sity of parks in the state park system (see table, 
page 4). Eastern coastal parks and recreation areas 
include beach and sound environments like those 
of Carolina Beach, Fort Fisher, Fort Macon, Goose 
Creek, Hammocks Beach, Jockey's Ridge, and 
Theodore Roosevelt. Coastal Plain parks such as 
Cliffs of the Neuse, Jones Lake, Lake Waccamaw, 
Merchants Millpond, Pettigrew, Singletary Lake, 
Waynesboro, and Weymouth Woods showcase the 
Sandhills, Carolina Bays, and other coastal envi- 
ronments. Piedmont parks and recreation areas 
such as Boone's Cave, Duke Power, Eno River, 
Falls Lake, Kerr Lake, Medoc Mountain, Morrow 
Mountain, Raven Rock, and William B. Umstead 
are characteristic of the rolling Piedmont and Fall 



Line areas. The western Piedmont and Mountain 
parks of Crowders Mountain, Hanging Rock, Lake 
James, Mount Jefferson, Mount Mitchell, New 
River, Pilot Mountain, South Mountains, and 
Stone Mountain, display the more spectacular, 
rugged terrains of those areas. 

Geology influences almost everything on the 
Earth. The hardness and structure of rocks influ- 
ence the landscape of our state. Rocks erode and 
weather to form soil, and thus, control the type of 
vegetation we see in an area and the crops we grow. 
Minerals provide us with raw materials to build 
cities, power cars, and heat homes. 

North Carolina has an unequaled variety of 
minerals. The discovery of a 17 pound gold nugget 
in Cabarrus County, in 1799, was the first discov- 
ery of gold in North America. Today, rockhounds 
enjoy looking for emeralds, rubies, and sapphires 
at commercial mineral collecting sites. Large 
mines and quarries yield valuable minerals, such as 
spodumene, phosphate, feldspar, mica, olivine, 
and pyrophyllite, that make North Carolina an im- 
portant contributor to the Nation's mineral supply. 
Gold continues to attract amateur prospectors as 
well as major exploration companies. 

North Carolina contains all three major rock 
types: igneous, metamorphic, and sedimentary. 
Some rocks are as old as one billion years, but 
others are only a few million years old. Some 
formed in the warm, calm waters of a shallow sea; 
others formed by heat and pressure deep in the 
Earth's crust. Still others were blasted fiery hot 
from now extinct volcanoes. 

Through the park system, North Carolina has 
showcased for its citizens a portion of the state's 
natural beauty. Protected from the aitack of bull- 
dozers and the desire of man to mold nature into his 
own image, the state parks are safe havens in a 
rapidly changing environment. Here, we are free to 
wander the trails, absorb the natural beauty, and 



reflect on the complex geologic processes that are 
in evidence around us. 

The Earth changes constantiy. As new 
rocks form, they are heated and cooled, folded and 
faulted, and go through the slow processes of grad- 
ual uplift and exposure at the surface. Here they 
weather and erode and are washed into rivers and 
ocean basins as sediments. These processes, con- 
tinuing today, are visible around us. As you walk 
the park trails, think about the changes the rocks 
have undergone to reach their present form. Rocks 
on top of Hanging Rock and Pilot Mountains were 
once sediments under the sea. Rocks in Eno River 
and Morrow Mountain State Parks were once 
blasted out of volcanoes. What processes shaped 
the Carolina Bays of Jones Lake, Lake Wac- 
camaw, Pettigrew, and Singletary Lakes? In an- 
other million years, how will nature have changed 
these areas? How will man's influence change 
what nature created? 

This guide is intended to increase your en- 
joyment of the state parks and to help you become 
more aware of the complex geology of our State. It 
will enable you to discover, first hand, the geologic 



principles you can only read about in textbooks. 
The geologic names used in this guide also appear 
on the 1985 Geologic Map of North Carolina. 
The Geologic Map of North Carolina and this 
publication provide background for understand- 
ing the geology of the State's 33 parks and recrea- 
tion areas, many of which are centered on out- 
standing geologic features. 

In many parks, there are trails too numerous 
to describe here. Many of these trails also reveal 
interesting geologic features but are less traveled 
by park visitors. Maps available in each state park 
show the additional trails. 

While enjoying your visit to the state parks, 
please leave the rocks for others to enjoy. Rock, 
mineral, and fossil collecting in state parks is not 
allowed by State law. 

Additional information on the geology and 
mineral resources of North Carolina is available 
from the North Carolina Geological Survey 
Section, P.O. Box 27687, Raleigh, N.C. 27611; 
phone (919) 733-2423. 




NORTH CAROLINA STATE PARKS 



Park 


Geologic Setting Geologic Province 


Major Geologic Points Of Interest 


COASTAL PLAIN 








Carolina Beach 


Coast 


Coastal Plain 


Dunes, sinkholes 


Cliffs of the Neuse 


River bank 


Coastal Plain 


Cliffs, fossils 


Fort Macon 


Barrier island 


Coastal Plain 


Beach stabilization, dunes, salt marsh 


Goose Creek 


Tidewater 


Coastal Plain 


Swamp, salt marsh 


Hammocks Beach 


Barrier island 


Coastal Plain 


Dunes, salt marsh, wave-cut scarp 


Jockey's Ridge 


Barrier island 


Coastal Plain 


Dunes 


Jones Lake 


Carolina bay 


Coastal Plain 


Carolina bay 


Lake Waccamaw 


Carolina bay 


Coastal Plain 


Carolina bay, fossils, peat 


Merchants Millpond 


Millpond 


Coastal Plain 


Surface sands 


Pettigrew 


Carolina bay 


Coastal Plain 


Carolina bay, peat 


Theodore Roosevelt 


Barrier island 


Coastal Plain 


Maritime forest, salt marsh 


Singletary Lake 


Carolina bay 


Coastal Plain 


Carolina bay 


Waynesboro 


River 


Coastal Plain 


River, floodplain 


Weymouth Woods 


Sandhills 


Coastal Plain 


Sandhills 


PIEDMONT 








Boone's Cave 


River 


Charlotte belt 


Cave, porphyritic granite 


Crowders Mountain 


Monadnock 


Kings Mtn. belt 


Kyanite, metasedimentary and metavol- 
canic rocks, monadnock 


Duke Power 


Lake 


Kings Mtn. belt 


Exfoliation, metamorphic rocks 


Eno River 


River 


Carolina slate belt 


Metavolcanic rocks, rapids 


Falls Lake 


Lake 


Raleigh beU- 


Igneous, metamorphic, and sedimentary 






Triassic 


rocks 


Hanging Rock 


Monadnock 


Inner Piedmont 


Monadnock, cliffs, cross-bedding, 
spheroidal weathering, waterfalls 


Jordan Lake 


Lake 


Traissic basin 


Triassic sedimentary rocks 


Kerr Lake 


Lake 


Raleigh belt- 
Carolina slate belt 


Fault zone, metamorphic rocks 


Lake James 


Lake 


Inner Piedmont 


Metamorphic rocks 


Medoc Mountain 


Fall line 


Eastern slate belt 


Gravel bar, joints, igneous and metamor- 
phic rocks, molybdenite 


Morrow Mountain 


Uwharrie Mtns. 


Carolina slate belt 


Bedding, flow banding, metavolcanic 
rocks 


Pilot Mountain 


Monadnock 


Inner Piedmont 


Cliffs, cross-bedding, inselberg, 
spheroidal weathering 


Raven Rock 


Fall line 


Eastern slate belt- 


Cliff, joints, metamorphic rocks, rapids, 






Raleigh belt 


river terraces, quartz veins 


South Mountains 


Foothills 


Inner Piedmont 


Cave, debris slide, metamorphic rocks, 
waterfalls 


William B. Umstead 


Piedmont 


Raleigh belt 


Igneous and metamorphic rocks, joints 


MOUNTAIN 








Mt. Jefferson 


Mountain 


Blue Ridge belt 


Mountain, metamorphic rocks, vistas 


Mt. Mitchell 


Mountain 


Blue Ridge belt 


Metamorphic rocks, mountain, vistas 


New River 


River 


Blue Ridge belt 


Igneous and metamorphic rocks, rapids, 
cliffs 


Stone Mountain 


Monadnock 


Inner Piedmont 


Exfoliation sheets, igneous and metamor- 
phic rocks, joints, monadnock, water 
falls, weathering pits, xenolith 



GENERAL GEOLOGY 



ics, aluminum production, greases, and medicine. 



rom the Blue Ridge and Great Smoky 
1 Mountains to the white sandy beaches of 
the Atlantic Ocean, the "Tar Heel" state has a 
variety of natural resources awaiting the traveler. 
North Carolina' s state parks are a showcase for the 
many geologic features in the State. The parks 
provide opportunities to explore the wonders of 
nature in a natural, unspoiled setting. 

North Carolina has a long and complex 
geologic history. Although much remains to be 
learned, detailed geologic studies provide a gen- 
eral understanding of regional geological relation- 
ships. The state is best described in terms of geo- 
logical belts; that is, areas with similar rock types 
and geologic history. 

Blue Ridge Belt: This mountainous region is 
composed of rocks from over one billion to about 
one-half billion years old. This complex mixture of 
granite, gneiss, volcanic, and sedimentary rock has 
repeatedly been squeezed, fractured, faulted, and 
twisted into folds. The Blue Ridge Belt is well 
known for its deposits of feldspar, mica, and 
quartz — basic materials used in the ceramic, paint, 
and electronic industries. 

Inner Piedmont Belt: The Inner Piedmont belt is 
the most intensely deformed and metamorphosed 
segment of the Piedmont. These rocks are about 
500-750 million years old. They include gneiss, 
schist, and granitic rock. The northeast-trending 
Brevard Fault zone forms much of the boundary 
between the Blue Ridge and Inner Piedmont belts. 
Although this zone of strongly deformed rocks is 
one of the major structural features in the southern 
Appalachians, its origin is poorly understood. 
Crushed stone for road aggregate and building 
construction is the principal commodity produced. 

Kings Mountain Belt: The belt consists of less 
intensely deformed and metamorphosed volcanic 
and sedimentary rocks. The rocks are about 400- 
500 million years old. World-famous lithium 
deposits are mined here. Lithium is used in ceram- 



Milton Belt: This belt consists of gneiss, schist, 
and metamorphosed intrusive rocks. The principal 
mineral resource is crushed stone for road aggre- 
gate and for building construction. 

Charlotte Belt: The belt consists mostly of igne- 
ous (rock crystallized from molten magma) rocks 
such as granite, diorite, and gabbro. These are 300- 
500 million years old. 

Carolina Slate Belt: This belt consists of heated 
and deformed volcanic and sedimentary rocks. It 
was the site of a series of oceanic volcanic islands 
about 550-650 million years ago. This belt is 
known for its numerous abandoned gold mines 
and prospects. North Carolina led the nation in 
gold production before the California Gold Rush of 
1849. In recent decades, only minor gold mining 
has taken place but mining companies continue to 
show interest in the area. Mineral production today 
is crushed stone and pyrophyllite which is used in 
refractory applications, insecticide carriers, wall- 
board, and latex foam fillers. 

Triassic Basins: These basins are filled with sedi- 
mentary rocks that formed about 200-190 million 
years ago. Streams carried mud, silt, sand, and 
gravel from adjacent highlands into rift valleys 
similiar to those of Africa today. The shales are 
mined and processed to make brick. North Caro- 
lina leads the nation in brick production. 

Raleigh Belt: The Raleigh Belt contains granite, 
gneiss, and schist. In the 19th century, there were 
a number of small building stone quarries in this 
region, but today the main mineral product is 
crushed stone for construction. In the 1980' s, the 
value of crushed stone produced in North Carolina 
exceeded $100,000,000 per year. For all mineral 
resources mined in North Carolina, the average 
return per acre devoted to mining yearly is over 
$20,000. 

Eastern Slate Belt: This belt contains slightly 
metamorphosed volcanic and sedimentary rocks 



similar to those of the Carolina slate belt. The rocks 
are poorly exposed and partially covered by 
Coastal Plain sediments. The metamorphic rocks, 
500-600 million years old, are intruded by 
younger, approximately 300 million year old, 
granitic bodies. Gold was once mined in the belt, 
and small occurrences of molybdenite, an ore of 
molybdenum, have been prospected here. Crushed 
stone, clay, sand, and gravel are currently mined 
in this belt. 

Coastal Plain: This province is a wedge of mostly 
marine sedimentary rocks that gradually thickens 
to the east. The Coastal Plain is the largest geologic 
area of the state, covering about 44% of the land 
area. The most common rock types are sandstone 
and clay, although a significant body of limestone 
occurs in the southern part of the Coastal Plain. In 
the Coastal Plain, geology is best understood from 
studying data gathered from well drilling. The 
state's most important mineral resource in terms of 
dollar value is phosphate, an important fertilizer 
component, mined near Aurora, Beaufort County. 



GEOLOGIC TIME SCALE 

Geologists use a geologic time scale to com- 
pare the ages of rocks. Refer to the Geologic Time 
Scale inside the front cover. The oldest rocks 
are at the bottom of the chart, the younger rocks 
are at the top. The ages may be expressed as 
relative ages, based on fossil dating, stratigraphic 
position, and crosscutting relationships of intru- 
sive rocks; or they may be expressed as absolute 
ages, based on isotopic dating (measuring the natu- 
ral radioactive decay of a rock or mineral). The 
time of metamorphic events can be determined by 
measuring the radioactive isotopes of new miner- 
als formed during metamorphism. 

Twelve geologic periods have been estab- 
lished so geologists can easily refer to a distinct 
period of geologic history; for example, theCam- 
brian Period refers to the time from 500 million to 
about 570 million years ago. The names are used 
throughout this guide to help compare the ages of 
rocks in various parts of the state. 




Geologic Belts From West To East 



Blue Ridge Belt 

|AVW 1 

t^^j Inner Piedmont Belt 

flflK Kings Mountain Belt 



Milton Belt 
Charlotte Belt 



Carolina Slate Belt 
Triassic Basins 
Raleigh Belt 
Eastern Slate Belt 



J Coastal Plain 



CAROLINA BEACH STATE PARK 
AND FORT FISHER RECREATION 
AREA 

Carolina Beach State Park is located in 
New Hanover County south of Wilmington. Fort 
Fisher, a state historic site, is 6 miles south of 
Carolina Beach State Park, along US Highway 

421. 

REGIONAL GEOLOGY 

The park is in the Coastal Plain physiogra- 
phic province. The Coastal Plain is a wedge of 
marine and nonmarine sediments that gradually 
thickens toward the coast. The sediments are of 
Jurassic to Recent age (200 million to 10 thousand 
years old) and overlie the east- sloping crystalline 
basement. A thin layer of younger sand and clay 
blankets the older sediments. In the vicinity of 
Carolina Beach, roughly paralleling the course of 
the Cape Fear River, the crystalline basement is 
gently bowed upward along the Cape Fear Arch, 
a prominent northwest-southeast trending struc- 
tural feature. Sediments at Carolina Beach are ap- 
proximately 1,530 feet thick; at Cape Hatteras the 
sediments are over 10,000 feet thick, illustrating 
how the thickness of the sediments increases away 
from the center of the arch. 

The park is located on the east bank of the 
Cape Fear River on the Cape Fear Peninsula. The 






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Cape Fear 



Coquina at Fort Fisher Recreation Area. 



northern boundary of the park is along Snow's Cut, 
an artificial waterway excavated to create access 
between the Cape Fear River and the Intracoastal 
Waterway. Carolina Beach is a mainland beach 
but displays many features characteristic of barrier 
islands because of the narrow peninsula width. At 
the southernmost tip of the peninsula is Cape Fear, 
one of 3 prominent capes along the North Carolina 
coast. 

Three capes (Cape Hatteras, Cape 
Lookout, and Cape Fear) occur along the North 
Carolina coastline. The location of these capes 
may be controlled by a hard, cemented coquina 
that underlies portions of the inner shelf. The 
coquina, or "beachrock," was formed along an 
ancient Pleistocene shoreline that is now partially 
immersed. Examples of this coquina can be seen at 
Fort Fisher where it crops out along the beach and 
in the banks of Snow's Cut near Carolina Beach 
State Park. The action of the circular currents 
(eddies) spinning off the Gulf Stream may also 
contribute to the development of the cape features. 

GEOLOGY 

Along the shoreline at Carolina Beach, 
modern coastal processes erode the beaches in 
response to slowly rising sea level. The creation of 



the man-made Carolina Beach Inlet caused ero- 
sion rates to accelerate. The overall movement of 
sand along the coast is from north to south. It is 
carried by longshore currents. Longshore cur- 
rents flow parallel to the shoreline and are caused 
by waves that approach the coast at an angle. When 
a wave breaks, individual sand grains wash up on 
the beach in the swash zone and are carried back to 
sea in a zig-zag pattern. Creation of the artificial 
inlet cut the steady southerly sand supply to the 
beaches south of the inlet, literally "starving" the 
Cape Fear Peninsula of sand needed to maintain the 
beach. 

On the western side of the peninsula are 
relict geomorphic features and sediments formed 
during the Pleistocene Epoch. Carolina Beach 
State Park lies entirely within this western area of 
the peninsula. 



TRAILS 

The walking trail begins at the southeast 
corner of the marina parking lot. The trail follows 
the east bank of the Cape Fear River, crossing in 
and out of the salt marshes and along the sandy 
river banks. Salt marshes trap sediment and help 
stabilize the peninsula. Approximately one mile 
from the beginning of the trail is a large stabilized 
sand dune called Sugarloaf. Sugarloaf attains a 
height of 55 feet above sea level. It is part of an 
east- west trending ridge of stabilized sand dunes of 
Pleistocene age. Sand dunes are eolian or "wind- 
blown" features. The east-west trend of these 
dunes reflects the ancient wind direction, and indi- 
cates that, during the Pleistocene, the predominant 
wind direction was different from the predominant 
wind direction today. Trees and grasses cover the 
dune. The fragile vegetation stabilizes the dune 
and protects it from the wind. Stabilized dunes 
protect beaches and barrier islands from erosion 
and are an important part of the beach profile. 



A series of small shallow ponds occur far- 
ther along the trail, north and east of the Sugarloaf 
sand dune. These ponds are sinkholes that formed 
in the Pleistocene coquina or shell limestone that 
underlies the park. Groundwater dissolves and 
weakens the limestone which then collapses to 
form sinkholes. Occasionally, sinkholes fill with 
water and become ponds. 

Other geologic features of interest are 
found in nearby areas outside the park boundary. 
Fossils can be collected along the banks of Snow's 
Cut, just north of the park boundary. These fossils 
are described in North Carolina Geological Survey 
Bulletin 89, Fossil Collecting in North Carolina. 
The same Pleistocene coquina that underlies the 
park can be seen along Snow's Cut. There it 
consists of a loose, unconsolidated sandy shell bed 
underlain by a hard, indurated crystalline coquina. 

Outcrops of the same hard, indurated co- 
quina occur along the northern end of Fort Fisher. 
They form a low ledge exposed at low tide along 
the shoreline. It is the only natural outcrop of beach 
rock along the North Carolina coast. For that 
reason, it is listed as a Natural Heritage Site and 
collecting or defacing the outcrop is prohibited. 
The coquina outcrop created the eroded bluff upon 
which Fort Fisher is located. At Fort Fisher, the 
coquina beds disrupt the normal north to south 
movement of sand; the hard limestone ledge is 
resistant to erosion and slows the steady flow of 
sand grains along the shoreline. The interruption of 
sand movement creates an imbalance between 
sediment supply and the capacity of the waves to 
carry sand. This imbalance results in a slight 
increase in erosion north of the coquina beds, and 
the pronounced erosion south of the beds that cre- 
ates the bluff at Fort Fisher. Attempts to reinforce 
the bluff with rip-rap (large boulders) only increase 
erosion rates along the coastline because the ob- 
struction disrupts the steady transport of sediment. 



CLIFFS OF THE NEUSE STATE PARK 

Cliffs of the Neuse State Park is located 
along the Neuse River in Wayne County, about 13 
miles southeast of Goldsboro, near the community 
of Seven Springs. Approximately 600 acres in 
size, most of the park is on the southwest side of the 
river. The park is appropriately named for its most 
spectacular natural feature, a sheer cliff. The cliff, 
ranging up to 90 feet high, forms the river bank for 
much of the river's traverse through the park. 



REGIONAL GEOLOGY 




Cliffs of the Neuse lies within the Coastal 
Plain region of the state. This is an area of generally 
low-lying, flat to gently rolling topography that 
extends from the coast to the Piedmont. Sedimen- 
tary rocks such as sandstone, clay, and limestone 
underlie the Coastal Plain surface. These sedi- 
ments dip slightly in a southeasterly direction and 
gradually thicken from a thin layer capping the hill 
tops at the fall line to nearly 10,000 feet thick at 
Cape Hatteras. They overlie steeply dipping 
folded and faulted crystalline rocks such as schist, 
gneiss, granite, and volcanic rocks similar to those 
that occur in the Piedmont. The Coastal Plain 
sedimentary rocks were deposited in a variety of 
marine to non-marine settings including shallow- 




A topographic map shows the deeply dissected terrain. 



shelf seas, rivers and floodplains, lagoons, 
marshes, estuaries, reefs, and dunes. 

The rocks of the Coastal Plain and their 
fossils tell a history of repeated advances and re- 
treats of the sea. The advances and retreats oc- 
curred when the elevation of sea level rose or fell 
relative to the elevation of the land. Sea level 
changes may result from two major causes. One 
cause involves global forces whereby land masses 
and ocean basins develop and change. As an ocean 
opens and widens through processes called rifting 
and drifting, sea level appears to drop. On the other 
hand, as a basin closes or as a new land mass forms, 
sea level appears to rise. Secondly, major climatic 
changes cause large amounts of sea water to be 
frozen or released from the Earth's polar ice caps 
generating changes in the elevation of sea level. 
These processes generally span tens- to hundreds- 
of-thousands-of-years. 

GEOLOGY OF THE CLIFFS 

The cliffs are composed of two main geo- 
logic units. The upper one is an unnamed surficial 
sand unit that contains white quartz pebbles in its 
lowermost part. This sand unit averages about 10 
feet thick along the cliff. The pebbles stand out on 
the cliff face because the loose sand that surrounds 
them is easily knocked away by wind and rain. 
Eventually, pebbles break free, fall down the cliff 
face, and are swept into the river. 



10 



The lower unit is below the pebble zoneand 
extends for about 200 feet below river level. This 
is the Black Creek Formation of Late Cretaceous 
age (66-96 million years old). This formation is 
widespread within the North Carolina Coastal 
Plain. Extensive areas of outcrop occur in the Tar, 
Neuse, and Cape Fear River valleys. 

On the cliff, the Black Creek Formation 
consists of a number of beds ranging from sand- 
stone to clay, with most being a mixture of sand, 
silt, and clay. The clays are usually dark gray to 
black. The sands are yellowish to white, although 
in some places they are stained red and cemented 
with iron-oxide. The. yellowish tint on the cliff is 
a surface coating of a sulfur compound. The sulfur 
comes from the breakdown of organic material 
such as leaves, twigs, and wood fragments that 
were deposited with the sand and clay. 

The Black Creek Formation in the park 
area is thought to have formed in a broad flat 
coastal zone. Certain environments in the coastal 
zone were habitats to specially adapted animals. 
Their remains sometimes were buried and pre- 
served as fossils. They are found in the cliff today, 
weathering out much as the pebbles in the upper 
bed are weathering. 

Parts of the modern day Louisiana and 
Mississippi gulf coastal zone resemble what ex- 
isted in the Cliffs of the Neuse area during deposi- 
tion of the Black Creek Formation. Within the 
cliffs are sediments probably deposited in a marsh. 
This is the dark clay bed near the top of the Black 
Creek Formation. Organic material is very abun- 
dant in this bed. Between clay layers are very thin 
layers of sand and silt that probably represent 
periodic flooding, perhaps associated with storm 
events or unusually high tides. 

Sandy beds, like those in the lower part of 
the cliff, indicate an environment subjected to cur- 
rents which swept away the finer-grained clay and 
silt. Some sort of channelized flow, perhaps in a 
wide and shallow tidal channel sweeping over the 



flat, may account for these deposits. 



HIKING TRAILS 

Spanish Moss Trail, Bird Trail, and 
Galax Trail have a combined distance of 1.75 
miles. They wind up and down the hilly topogra- 
phy of the park adjacent to the Neuse River. Such 
topographic relief is unusual for the Coastal Plain 
as a whole, but not uncommon for areas that lie 
along the southwest sides of the major rivers and 
streams. These are usually the steepest drainages 
in the eastern part of the State. 

Geologic exposures like those along the 
Neuse River are not present along the trails. Except 
on sheer cliffs or similar rapidly eroding areas, the 
Coastal Plain sediments are readily altered to soil, 
and vegetation takes hold. The soil also tends to 
"creep" slowly downslope and obscure any geo- 
logic exposures. 

The Spanish Moss Trail starts at the inter- 
pretive center and loops down to the Neuse River 
floodplain before returning to the center. One steep 
slope or face near the junction of the loop of this 
trail exposes sandy sediments of the Black Creek 
Formation. 

The Bird Trail follows the river for a short 
distance downstream from the cliffs overlook be- 
fore turning up, across and back down Still Creek. 
Before its junction with Mill Creek, Still Creek 
cascades over a small series of iron-oxide ce- 
mented sandstone layers within the Black Creek 
Formation. These dark red (striped) rocks may be 
seen from the trail. 

Galax Trail follows Mill Creek before 
looping back and merging with Bird Trail. Be- 
tween Galax Trail and Mill Creek, limestone boul- 
ders containing molds and casts of shells are vis- 
ible. Loose, white sand of the B lack Creek Forma- 
tion covers much of the middle portion of the trail. 
(Sample collecting in the park is prohibited). 



11 



BARRIER ISLANDS 

The Atlantic and Gulf Coast barrier island 
chain is the longest and best developed in the 
world. However, it is not unusual since similar 
island chains occur along nearly all gently sloping 
coasts. Their origin varies from region to region 
depending on the geologic history, the nature of 
ocean currents operating in the region, and the 
supply of sand available to the coastal system. 

These islands lie seaward of bays, sounds, 
or lagoons and are often separated from each other 
by narrow channels called inlets. Tides cause 
water to flow in and out of the shallow bodies of 
water behind the barrier islands through the inlets. 

North Carolina's Outer Banks originated 
10,000 to 12,000 years ago as coastal dunes when 
sea level was much lower than its present elevation. 
The shoreline was some 40 miles seaward of its 
present location. Since that time sea level has been 
rising. Initially, the sea level rise was quite rapid as 
continental glaciers retreated and supplied large 
amounts of water to the oceans. The rate has 
slowed over the last 5,000 years to an estimated 
one foot rise per century. 

When sea level began to rise, it broke 
through low areas of the coastal dunes and flooded 
the low-lying area behind them. As sea level con- 
tinued to rise, the barrier chain moved along with 
the migrating coast as the ocean-side material was 



constantly transported to the sound or lagoon side. 
Three main processes account for the transport of 
material from the ocean to the sound. One is the 
movement of sediment through inlets by the tide. 
On each tidal cycle the flood of water into the sound 
carries sand and mud, and deposits it much in the 
way a river builds a delta at its mouth. Hence, the 
term tidal delta is used to describe the deposits that 
form on the sound side of inlets. Inlets eventually 
migrate to another location or simply become 
choked with sediment, while a new inlet forms 
elsewhere and the tidal delta deposits become part 
of the barrier. 

Sand dune migration is another process by 
which barrier islands grow in a landward direction. 
Onshore flowing breezes blow sand derived from 
the beach up and over the dune crests. In this 
manner they grow on the sound side and build 
steadily in a landward direction. 

The third main process accounting for 
barrier island migration is overwash. This is often 
a sudden event, usually associated with unusually 
high tides driven by storms. In overwash, the sea 
breaks through the dunes at a vulnerable point and 
a fan of sediment is deposited on the back side of 
the barrier. Sometimes the breach remains open as 
an inlet, but usually dunes reform in the low area. 

Fort Macon, Hammocks Beach, and 
Jockey's Ridge are good parks in which to see 
barrier island processes. 




Bear Island. 



12 



FORT MACON STATE PARK 

Fort Macon State Park is located in Car- 
teret County, east of the town of Atlantic Beach. 
The park is on the tip of a stretch of barrier islands 
called Bogue Banks. Beaufort Inlet forms the east- 
ern park boundary. The port of Morehead City lies 
on the mainland across Bogue Sound. 



BARRIER STABILIZATION 

Barrier migration is a process common to 
all barrier islands. Migration of Bogue Banks is 
well evidenced by samples from boreholes drilled 
in the island. They show marsh and sound deposits 
underlying the present dune system. Sometimes 
winter storms expose the dark colored muddy salt 
marsh sediments when the pounding waves erode 
unusually large amounts of beach sand. Many of 
the shells found along the beach are fossils that 
waves washed up from several thousand-year-old 
lagoon deposits exposed on the ocean side of the 
barrier islands. 

A sea level rise of one foot per century 
produces about 5 feet per year of shoreward barrier 
migration along Bogue Banks. Efforts to halt the 
natural process are evident in the park and its 
general vicinity. Most obvious is the massive stone 
jetty built to trap sand moving along the beach front 
and keep it from filling Beaufort Inlet. The jetty 
caused a build up of sand on the park side but 
erosion on the inlet side. The project is not 100% 
effective, but it helps to decrease the amount of ex- 
pensive dredging required to keep the channel 
open. 

Two major rock types were used to con- 
struct the jetty. One is limestone containing casts 
and molds of the hard parts of shell fish and other 
organisms that made up the original rock deposit. 
The other rock, granite, ranges from pink to gray 
in color. The limestone, which is 30-40 million 
years old, is young compared to the several 
hundred million-year-old granite. Both rock types 
were quarried inland and transported to the coast. 




Fort Macon 
State Park 



Several short jetty-like structures, called 
groins, were built out from the shoreline in the park 
to help stabilize the beach. Groins, like jettys, are 
designed to trap sand moving along the beach. 

Beach replenishment is also used in the 
effort to maintain the beaches of Bogue Banks. 
This process involves pumping dredge spoils from 
Beaufort Inlet onto the beach front to replace sand 
which was lost to erosion. Often the sand pumped 
onto the beach remains only temporarily because 
the added sand steepens the beach profile. This, in 
turn, accelerates erosion and the new material is 
gone in a few seasons. 



BARRIER ISLAND ENVIRONMENTS 

Three major barrier island environments 
occur in the park. These are the salt marsh, which 
is present on the sound side of the island; the mari- 
time shrub thicket, a band of thick vegetation along 
the center of the island in the park; and the dune/ 
beach environment which fronts the ocean and lies 
mostly on the seaward side of the park road. 

The salt marsh is not easily accessible 
except by boat; however, it can be seen along the 
sound from the park road immediately after enter- 
ing the park. Salt marshes develop in the relatively 
quiet waters of the sound on "new" land formed by 



13 



washover and tidal delta deposits. Cordgrass and 
other salt tolerant plants able to withstand repeated 
tidal flooding are common in salt marshes. 

The maritime shrub thicket lies seaward of 
the salt marsh on land above the high springtide 
level. This environment consists of low-growing 
wax myrtle, black locust, red cedar, beach holly, 
cat briars, and prickly pear cactus. Scattered pock- 
ets of small live oaks indicate the beginnings of a 
maritime forest environment. A good example is 
along the ocean side of the park road just past the 
entrance to the bath house and picnic area. Roosev- 
elt Natural Area, located about 12 miles west of the 
park, consists of mature maritime forest vegeta- 
tion. The Elliott Coves Trail begins near Fort 
Macon and continues through the maritime shrub 
thicket before winding back to the parking lot 
along Beaufort Inlet. 



Dunes built by blowing sand face the ocean 
immediately behind the beach. Dunes represent 
the first line of defense against the sea. Areas 
where the dune system is low or narrow are most 
susceptible to erosion and overwash. Conversely, 
areas where the dune system is well developed and 
stabilized by vegetation, such as sea oats or beach 
grass, will best survive the force of the sea. Some 
dunes in the park are 40 feet high. 

Evidence of active barrier migration is seen 
by the way the dunes are drifting into the maritime 
shrub thicket. In turn, as the salt marsh receives ad- 
ditional sediment from tidal floods or periodic 
overwash, it will be overtaken by shrub thicket 
vegetation. Similarly, the salt marsh will continue 
to expand into the sound and the dynamic process 
of barrier island migration will continue. 




Fort Macon State Park is located on Bogue Banks, one of the state's barrier islands. Bogue Sound lies between 
the island and the mainland. 



14 



HAMMOCKS BEACH STATE PARK 

Hammocks Beach State Park is located on Bear 
Island 4.5 miles west of Swansboro. It is reached 
by a free passenger ferry during the summer 
months or by private boat year round. The ferry 
landing is at the end of secondary road 1511, south 
of Swansboro. The park has one of the most 
beautiful, unspoiled beaches on the Atlantic coast. 



GEOLOGIC FEATURES 

The major features of Hammocks Beach State 
Park are 1) extensive salt marsh and the lack of 
open sound on the land side of the island, 2) a large 
area of shifting dunes, 3) Hmited areas of thicket or 
forest, 4) a wave-cut scarp behind the beach, and 5) 
shifting inlets. 

Bear Island is slowly moving landward by the 
following process. Sand is brought to the beach 
from the nearby ocean floor by waves and currents. 
The prevailing winds carry the sand from the beach 
area up onto a new dune forming behind the beach. 
The wind then pushes the sand up the side of the 
dune until it reaches the top of the dune and slips or 
avalanches down the other side. Vegetation on the 
dune catches or deflects the shifting sand and 
influences the shape and landward progression of 
the dune. Finally, the active dune shifts across the 
island into the salt marsh at the landward side of the 
island. Trees and shrubs of the small forested areas 




Fort Macon 
State Park 



are, in some places, covered by the dune. Inlets at 
both ends of the island also shift constantly. In the 
last 30 years, Bogue Inlet at the northeast end of the 
island has shifted more than Bear Inlet at the south 
end of the island. 

One interesting feature along this part of North 
Carolina's coast is the age of the seashells found on 
the beach. Many of the shells are between 7,000 
and 9,000 years old. Some of the shells are from 
animals that lived on the landward side of the 
island. These shells were uncovered after the 
island migrated landward. The sea rips up old 
lagoon deposits which are now exposed just off 
the beach. The shells are finally washed onto the 
beach. 



COASTAL AREA 



UPLAND 



Dune 



BEACH OR SHORE 



BACKSHORE 



FORE- 



SHORE 



ZONE OF 
NEARSHQRE CURRENTS 



INSHORE OR SHOREFACE 



Breakers 




Beach Scarp 



Crest of Berm/ Low Water Level 

Plunge Point 



-V 



OFFSHORE 



Beach terminology. 



15 



JOCKEY'S RIDGE STATE PARK 

Jockey's Ridge State Park, located on the 
North Carolina Outer Banks at Nags Head, features 
the highest sand dune on the eastern United States 
coast. The dune towers up to 100 feet above the 
surrounding low-lying countryside and is visible 
from many miles away. 

The park is located on Bodie Island, 10 
miles northeast of Manteo, via U.S. highways 64 
and 158. Jockey's Ridge is the largest and highest 
of a series of dunes that includes Run Hill, Engage- 
ment Hill, Pin Hill, and Seven Sisters. The first 
lands for the park were purchased in 1975 in re- 
sponse to an increasing public desire to protect the 
dune from encroaching development from Nags 
Head. 



GENERAL GEOLOGY 

Sand dunes are comprised of wind blown 
sand. Development of dunes relies heavily upon 
the establishment of vegetation or some other 
agent such as sand fencing which can slow down 
the wind and reduce the wind's capacity to move 
the sand. Wind with a velocity of about 12 miles 
per hour will transport dry, loose sand. On the 
Outer Banks, sea oats and other types of beach 
grass are the primary agents which aid dune devel- 










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opment. Continued development of the dune 
depends on its ability to survive erosive forces such 
as ocean flooding or man's influence. Migration of 
the dunes will tend to diminish, or the dune will sta- 
bilize, as vegetation gains a foothold on the dune 
and roots hold the sand in place. 

Just as the factors controlling dune devel- 
opment and migration are irregular, sporadic, and 
interrelated, so is the history of any particular dune 
or dune complex. Our knowledge of the Jockey's 
Ridge dune is limited to historical accounts. The 
dune dates back at least to the time of early French 
and Spanish exploration of North America. In the 
early 1800's, the Nags Head area, with Jockey's 
Ridge as a prominent attraction, was a popular 
vacation resort. 

Aerial photographs from 1949 to the pres- 
ent indicate no appreciable changes in the size or 
location of the dune complex except for a very 
gradual southwestward migration. Individual 
peaks and depressions within the dune area vary in 
size and location seasonally or over periods of 
several years, but the overall change is not signifi- 
cant. This is because the wind patterns for the area 
tend to "cancel" each other. Dune migration 
caused by southeast winds is counteracted by mi- 
gration caused by northeasterly winds. The south- 
east winds are dominant from March through 
August. The northeast winds are dominant from 
September through February. 



16 



A number of features and processes may be 
observed within the park. First is the sand itself. It 
is mostly fine grained and well sorted (the major- 
ity of the grains are the same size). Finer grained 
material is blown away or winnowed because it is 
lighter and more easily transported by the wind. 
Coarser grained materials, such as gravel, are too 
heavy to be carried to the dune area from the beach 
except by flooding or by very strong winds. The 
abrasive action of the sand grains striking each 
other as they move along the dune's surface tends 
to break off any edges, thus giving the grains a 
rounded form. This process, nothing more than 
natural sand blasting,, creates a frosted surface on 
the grains. 

The sand is comprised chiefly of the min- 
eral quartz. In lesser amounts, other minerals such 
as feldspar, mica, calcite (from broken shells), and 
a group of dark minerals, collectively referred to as 
heavy minerals, are found in the dune environ- 
ment. The heavy minerals are most noticeable 
where they are concentrated in individual layers or 
laminations. This occurs because lighter-weight 
minerals are blown away by winds not strong 
enough to transport the heavy minerals. 

The internal dune structure consists of thin 
layers, called cross-beds or cross-laminations, 
which lie at various angles to the overall dune form. 
They form on the leeward side (side away from the 
wind) and record the direction of the wind that de- 



posited the layer. A set of cross-beds represents 
only a very short period of time, perhaps only days, 
of the dune' s history. The angled accumulations of 
sand are generally exposed on portions of the 
windward side of the dune as covering sand is 
blown away. 

In addition to the peaks and ridges of the 
dune system, there are also bowl-like depressions 
which are called blowouts. Blowouts result from a 
process known as deflation. This occurs when 
turbulent wind currents scour out the depression. 
The trail from the parking lot opens up into a 
blowout area. As deflation proceedes, vegetation 
root systems become exposed and the plants die, 
thus increasing the area's vulnerability to further 
deflation. Sometimes deflation advances to the 
point where the surface is scoured down to the 
water table and the result is a pond in the blow-out 
area. 

Dune areas, and especially Jockey's Ridge 
because of its height, are often the location of 
lightning strikes. On rare occasions, the energy of 
the lightning bolt fuses the sand to form fragile, 
irregularly shaped tubular or cone-shaped glass 
objects called fulgurites. They generally are 
found on the higher elevations after surrounding 
loose sand is blown away to expose the fulgurite. 
Fulgarites that have been found in the park are up 
to several inches in length and about one-half inch 
in diameter. Sometimes they have a branching 
form. 




Cross-bedding in the dunes at Jockey's Ridge. The dark layers are heavy mineral concentrations. 



17 



MERCHANTS MILLPOND 
STATE PARK 

Merchants Millpond State Park is located 
in central Gates County, 6 miles northeast of 
Gatesville. The Millpond covers approximately 
500 acres behind a dam built across Bennetts 
Creek, a tributary of the Chowan River. Corn and 
wheat milling operations at the site date back to 
1812. 



GENERAL GEOLOGY 

The park area is underlain by sand and clay 
of Quaternary age (up to about 2 million years 
old). Quaternary deposits similar to these blanket 
the surface of most of the state's Coastal Plain. 
Information from a water well drilled in the park 
indicates that this uppermost geologic unit is about 
50 feet thick. Below the surface unit, shell marls, 
sand, sandstone, clay, and some limestone extend 
to a depth of about 1,500 feet. 

The Atlantic Coastal Plain is underlain 
by a sequence of sedimentary rocks whose thick- 



MURFREES 




ness ranges from a few feet, where it laps onto the 
crystalline rocks of the Piedmont region, to nearly 
10,000 feet at Cape Hatteras, and even thicker 
offshore. These sedimentary rocks have accumu- 
lated for over 100 million years along the gradually 
sinking or subsiding margin of the North American 
continent. 

Although the overall effect has been a sub- 
siding continental margin, the different types of 
sediments found in wells drilled in the Coastal 
Plain indicate that the process that formed the 
sediments was complex. For example sedimen- 
tary rocks that were deposited in a shallow ocean 
setting occur as far inland as Raleigh. Also, in the 




Merchants Millpond. 



present day offshore area, deposits that were laid 
down along the banks of rivers and streams of an 
emerged Coastal Plain are now found in the subsur- 
face. These findings demonstrate that the ocean has 
migrated back and forth across the continental 
margin in a series of transgressions and regres- 
sions. 

The sea left behind a series of flattened 
surfaces or terraces that decrease in elevation from 
the Piedmont to the present shoreline. Some ter- 
races are separated by somewhat steeper slopes 
called escarpments which represent former barrier 
islands. In some areas features such as preserved 
ancient dunes or inlets are associated with the es- 
carpments. 

As many as seven terraces are interpreted 
along the Atlantic Coastal Plain. Localized move- 
ments of the earth and erosion of the terraces, es- 
carpments, and associated features, however, have 
made recognition of the upper terraces difficult and 
subject to more than one interpretation. In the 
lower elevations of the Coastal Plain, the features 
are more clearly delineated. For example, a fairly 
continuous escarpment known as the Suffolk 
Scarp can be traced on topographic maps, aerial 
photographs, and satellite photographs through 
Beaufort, Washington, and eastern Gates counties. 
This 10-15 foot high escarpment separates the 
lowest Coastal Plain terrace, which lies east of the 
scarp, from a second terrace. Merchants Millpond 
State Park lies in the second trerrace. 

In the park area the terrace elevation is 
almost 40 feet above sea level. Bennetts Creek and 
its tributary streams have eroded down into, or 



dissected, this terrace to form flat, swampy flood 
plains which lie at elevations of less than 10 feet. 
The average elevation of the Millpond is 6.5 feet. 

Slopes formed between the terrace and the 
bottom lands are relatively steep compared to other 
areas of the Coastal Plain. This combination of 
steep slopes and deeply cut drainages is especially 
favorable for the creation of artificial lakes and 
ponds by building dams where the valleys narrow. 
This may account for the apparent abundance of 
millponds in the northern Coastal Plain as com- 
pared to the central and southern parts. 

The park's interpretive center houses an 
exhibit of Indian artifacts found within the park. 
Since there are no natural outcrops of hard rock in 
the immediate vicinity of the park, these crude 
tools must be made from rocks that were found 
elsewhere. One rock type can be identified as 
coming from the Kinston area. This is a hard, dark 
gray mudstone unique to that area. The white or 
cream colored sandstone originated in the Pied- 
mont or possibly the mountains of Virginia. Rocks 
similar to these are found in the surficial deposits of 
southeastern Virginia. They may have been car- 
ried this far into the Coastal Plain by floods. Some 
of the larger boulders may even have been trans- 
ported in ice blocks which formed in the upper 
reaches of the ancestral James River. The blocks of 
ice floated downstream and eventually dropped the 
boulders as the ice melted. The gnarled stumps of 
trees swept downstream in floods also can trans- 
port large boulders. The discovery of these rare but 
essential hard items was likely an important event 
to the former inhabitants of the lower Coastal Plain. 



19 



CAROLINA BAYS 

Shallow, oval depressions called Carolina 
Bays occur in the Atlantic Coastal Plain from 
Florida to New Jersey. The extent of the bays was 
not truly known until aerial photographs became 
available, revealing the large number and nature of 
these striking geomorphic features. It is estimated 
that there are as many as 500,000 bays, the major- 
ity of which are in North and South Carolina, hence 
the name Carolina Bays. The greatest concentra- 
tion of bays is in the swampy area northeast of the 
Cape Fear River in Bladen County. 

Rather than describing a body of water, the 
term bay, in this case, refers to the distinctive vege- 
tation, such as loblolly bay, that fills these depres- 
sions. All the depressions were once lakes; how- 
ever, the vast majority were filled naturally with 
sediment and vegetation or were drained for agri- 
culture. Only a few bays still contain water. By 
studying pollen grains, geologists have determined 
that these bays were formed 40,000 years ago 
during the Pleistocene Wisconsin Ice Age. No 
Carolina Bays are being formed today. 

r ''**&£%.« 



Many theories have been proposed to ex- 
plain the formation of Carolina Bays. These theo- 
ries generate much debate among scientists but no 
agreement has been reached. These theories are 
explained below. 



GEOMORPHOLOGY 

Carolina Bays are shallow, elliptical de- 
pressions oriented in a southeast-northwest direc- 
tion. Bays are only found in the loose, unconsoli- 
dated sands that form a cover within the Coastal 
Plain. The greatest concentration of Carolina Bays 
is in Bladen and Columbus Counties where, in 
some areas, they cover up to 50 percent of the land 
surface. A sand rim is present around most bays 
and is usually best developed along the southeast 
end of the bay. The sand rim is thought to be 
formed by wind action on the bay. 

While a small number of Carolina Bays 
still contain water, most are completely over- 
grown. The bays have dense vegetation with a 
distinctive plant community including loblolly 










3& 








Aerial photograph showing the concentration of Caro- Bay lake geomorphology. 
Una Bays in the Coastal Plain. 



20 



bay, red bay, and sweet bay. The barren sand rim, 
in contrast, is nutrient-poor and dry with little or no 
soil development or water-holding capacity. It 
supports only sparse stands of turkey oak, long leaf 
pines, mosses, and wire grass. Carolina Bays can 
be distinguished from surrounding areas on the 
basis of vegetation alone. Bays that still contain 
water were at one time much larger water bodies 
but are gradually shrinking in size as the vegetation 
continues to take over. 

Peat deposits formed in Carolina Bays as 
part of the natural lake filling or "overgrowth" 
process. Peat consists of partially decomposed 
plant material that is formed as plants die and are 
buried in the swampy, organic-rich environment of 
the Carolina Bays. The tea-colored water in most 
water-filled bays is formed by the leaching of 
humic acid from the peat deposits. Today, peat 
deposits are considered a potential source of en- 
ergy. Extensive peat deposits in the Coastal Plain 
of North Carolina formed in pocosins along the 
coast and in Carolina Bays. These peat deposits are 
described in Bulletin 88, Peat Deposits of North 
Carolina, available from the North Carolina Geo- 
logical Survey Section. 



THEORIES OF ORIGIN 

Many theories have been proposed to ex- 
plain the origin of the Carolina Bays. These 
include: 1) meteorite impact; 2) solution by arte- 
sian springs and streamlining of bays by wind and 
current action; 3) solution of limestone and 
streamlining of bays by the flow of groundwater; 4) 
the activity of fish swimming around submarine 
springs; and 5) oriented lakes. While there is no 
general agreement on the origin of the Carolina 
Bays, the oriented lakes theory is best supported by 
scientific evidence. 

The meteorite impact theory suggests that 
the Carolina Bays were formed by a swarm of me- 
teorites that crashed into the earth at a low angle 



from the northwest. It is suggested that air shock 
waves, generated by meteorite impacts, created the 
shallow, elliptical depressions in the loose, uncon- 
solidated sands that blanket the Coastal Plain. Ac- 
cording to this theory, the shape of the bays was 
also influenced by the earth' s rotation at the time of 
impact. This theory is still very popular but is not 
well supported scientifically. No meteorite mate- 
rial has been found in the bays, and a subbottom 
profile of Singletary Lake shows no evidence of 
disturbance such as a meteorite impact would 
make. 

Theories of bay development by artesian 
springs or the solution of limestone by groundwa- 
ter have been discounted because many Carolina 
Bays are found outside of areas where artesian 
springs develop or limestone occurs. 

The oriented lake theory is the most widely 
accepted theory of bay formation. Oriented lakes 
are elliptical lakes that have a consistent orienta- 
tion along the long axis of the lake. The theory 
states that Carolina Bays were ponds of water 
streamlined by the erosive action of wind-gener- 
ated lake waves. Over time, the prevailing winds 
cause the water to erode rapidly along the ends of 
the lakes perpendicular to the direction of the pre- 
vailing winds. This process results in an elliptical 
lake oriented perpendicular to the direction of the 
prevailing winds. 

In the area of the Carolinas, according to 
this theory, prevailing winds from the north-north- 
east created the southeast-northwest orientation of 
the Carolina Bays. After the lakes stabilized, sand 
dunes developed in response to strong intermittent 
northwest winds. This is evidenced by the well de- 
veloped sand rims on the southeast end of the bays. 
As the climate changed and warming began after 
the Wisconsin Ice Age, precipitation decreased 
and the bays filled with water more slowly. The 
bays began to be overtaken by vegetation. This 
"overgrowth" process continues today. 



21 



LAKE WACCAMAW STATE PARK 

Lake Waccamaw State Park is located at 
the end of State Road 1947, 6 miles southeast of the 
town of Lake Waccamaw in Columbus County. 

Lake Waccamaw is the largest Carolina 
Bay that still contains water and is the second 
largest of all Carolina Bays. It is approximately 6 
miles long and lies at an elevation of 43 feet above 
sea level. Maximum water depth is 1 1 feet. A sand 
rim, located along the southeastern edge of the 
lake, is 23 feet high and 2,000 feet wide. Lake 
Waccamaw State Park is within this sand rim. 

Lake Waccamaw forms the headwaters of 
the Waccamaw River which flows from the south- 
western edge of the lake. Big Creek flows into 
Lake Waccamaw along the northeastern edge of 
the lake. Exposures of the Upper Cretaceous 
Peedee Formation, the Pliocene Duplin Forma- 
tion, and the Pliocene-Pleistocene Waccamaw 
Formation are in a 15 foot bluff that is on the 
northeastern shore of Lake Waccamaw. The water 
in most Carolina Bays is naturally very acidic, but 
the water in Lake Waccamaw is neutral because of 
the solution of limestone which underlies the lake. 
An outcrop of this limestone occurs along the 
northeastern edge of the lake. 

Lake Waccamaw is a unique Carolina Bay 
in that it has a sandy bottom along the entire shore. 






k CLINTOI\ 




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Peat deposits lie in a northwest-southeast-trending 
band in the middle of the lake. 



SINGLETARY LAKE STATE PARK 

Singletary Lake State Park is located on the 
east side of North Carolina Highway 53,12 miles 
southeast of Elizabethtown in Bladen County. The 
lake is 70 feet above sea level and lies in a low, 
poorly drained, swampy area northeast of the Cape 
Fear River. 

The Upper Cretaceous Black Creek For- 
mation underlies this area and is covered by a 
veneer of surficial deposits of Pleistocene age. The 
Black Creek Formation consists of a mica-rich 
gray to black sandy clay and sand. Fine lignite and 
sulfur are commonly found throughout the forma- 
tion. A classic outcrop of the Black Creek Forma- 
tion is at Walkers Bluff on the Cape Fear River near 
Singletary Lake. 

The road to the bunkhouses and pier is 
located in the sand rim along the southeast side of 
Singletary Lake. The sand rim supports very little 
vegetation; it has a stark, almost desert-like appear- 
ance that is very striking. 



Aerial photograph showing Singletary Lake. 



22 



North Carolina Highway 53 follows the 
southwest edge of Singletary Lake. On the east 
side of the road is the dense bay bog vegetation 
characteristic of Carolina Bays. The west side of 
the road is the sparsely vegetated sand rim. Stabi- 
lized sand dunes can be seen along the dirt road that 
runs along the east side of Singletary Lake. Again, 
in this area you can view the striking contrast 
between the sand rim and the vegetation-filled 
areas of the bay. (The rare Venus Fly Trap plant 
grows along the border between the sand rim and 
bay bog.) 



JONES LAKE STATE PARK 

Jones Lake State Park is located on the west 
side of North Carolina Highway 242, 4.5 miles 
north of Elizabethtown in Bladen County. 

Jones Lake, like Singletary Lake, is a clas- 
sic example of a water-filled Carolina Bay. It is 60 
feet above sea level. The general recreation area 
and campsites are located in the sand rim along the 
southeastern part of the bay. A nature trail around 
the perimeter of the lake provides the unique op- 
portunity to walk through the densely vegetated 
bay bog area of a Carolina Bay. 



PETTIGREW STATE PARK 

Pettigrew State Park is 9 miles south of 
Creswell on the northern shore of Lake Phelps. 
Lake Phelps is a 16,600 acre water body that lies 
on the Pamlimarle Peninsula between the Albe- 
marle Sound and Pamlico River. A sand rim is 
absent around Lake Phelps, a factor in the argu- 
ment against considering this lake as a Carolina 
Bay. On the other hand, the shape and orientation 
of the lake are factors that support the idea that the 
lake is a bay. It may be, in fact, a double bay. 



This area consists of vast, low-lying 
swampy land which includes bays, marshes, and 
fresh- water wetlands known aspocosins. The area 
has gradually yielded to development since its 
settlement in the late 1700' s. Exploitation of the 
rich timber resources was followed by ditching and 
the building of canals for better drainage and for 
transportation. This, in turn, promoted agriculture, 
the primary resource of the area for over a century. 

In the early 1970's, oil embargos and soar- 
ing fossil fuel prices generated commercial inter- 
est in the area' s huge peat resources. The extensive 
peat deposits of the Pamlimarle Peninsula devel- 
oped over the past 10,000 years as the decaying 
leaves, roots, and stumps of lush vegetation accu- 
mulated in stream channels, shallow lakes, and 
fresh-water marshes. These deposits are locally 
greater than 10 feet thick but average about 4 feet 
thick. Within the Pamlimarle Peninsula, peat 
deposits cover a total area of over 350,000 acres. 
Bulletin 88, Peat Deposits of North Carolina, 
locates and describes the peat deposits. This pub- 
lication is available from the N.C. Geological 
Survey. 




23 



WEYMOUTH WOODS SANDHILLS 
NATURE PRESERVE 

Weymouth Woods Sandhills Nature Pre- 
serve is in Moore County, approximately 1 mile 
southeast of Southern Pines off highway U.S. 1. 
This 628 acre preserve is bounded by Ft. Bragg- 
Aberdeen road (SR 2074) to the south and Con- 
necticut Avenue to the north. The preserve is in the 
southwestern portion of the Coastal Plain Physi- 
ographic Province in an area known as the 
Sandhills region. 

Mill Creek, an east-west trending tributary 
of James Creek, divides the preserve almost 
equally into north and south areas. The creek 
contains a swampy floodplain (Jones Creek 
swamp) that in places is more than 250 feet wide. 
A striking feature of this drainage is its elevation in 
relation to the local topography immediately to the 
north and south. To the south, at the preserve 
entrance, sand-capped hills form topographic 
highs 500 feet above mean sea level. To the north, 
130 feet below the base of these hills, lies the 
incised channel of Mill Creek. This 130 foot 
difference in elevation occurs in a horizontal dis- 
tance of less than 2,500 feet. The hills to the north 
of the creek are 460 feet above mean sea level at 
their highest point. This hilly Sandhills topogra- 
phy reflects a geologic history of uplift followed by 
dissection. 



GEOLOGY 

Sedimentary rocks in Weymouth Woods 
Sandhills Nature Preserve formed through a com- 
plex sequence of events millions of years ago. This 
sedimentary sequence gives us insight into the 
local and regional geologic history of the Preserve 
and its relationship to the one million acre area 
known as the Sandhills region. 

Most of the sands capping ridges in the 
S andhills region belong to the Pinehurst Formation 
of Tertiary age. Geologists do not agree on the 
origin of these sands. Many geologists once 



Historic 

Hillsborough Eno River 
State Park 



PINEHURS 




thought that the sands were eolian, or wind blown, 
in origin. Recent studies suggest that they formed 
in a shallow, relatively quiet water embayment. 
Similar sands of marine origin in nearby Harnett 
County are described as Eocene in age. Eocene 
age rocks also occur south of Weymouth Woods. 
Regardless of the formation of the Pinehurst For- 
mation, the surface sands have been reworked by 
winds during recent times. 

The high-level layers of loose, light-col- 
ored sands of the Pinehurst Formation that cap the 
hills are significant because they contain large 
amounts of white quartz with only a few other 
minerals. The distinctive rolling, hilly terrain and 
high topographic position of these sands are the 
primary reasons the Sandhills are so named. Else- 
where, . the Sandhills are a source of quartz for the 
manufacture of high-quality glass products. 

Underlying the sands of the Pinehurst For- 
mation are poorly indurated sandstones and sandy 
clays of the Middendorf Formation. The Midden- 
dorf Formation in turn overlies slightly more indu- 
rated sandy clays and clayey sands of the Cape 
Fear Formation. 

The sedimentary rocks of the Middendorf 
Formation are best exposed in the northern half of 



24 



Weymouth Woods away from the drainage basin 
of Mill Creek. They are interlayered reddish- 
brown to orange-brown sandstone and sandy clay. 
The sandstone is cross-bedded with beds lying at 
angles to each other. Occasional gravel beds, iron- 
cemented sandstone, and petrified wood are found 



within this area of the preserve. 

The Cape Fear Formation has not been 
recognized at the surface in the vicinity of the 
preserve but has been encountered in wells around 
Southern Pines. 




Selected Coastal Plain fossils. 

Top left. Periarchus lyelli (Conrad), 1834a, UNC 7611, 
Eocene Castle Hayne Formation at the Martin Marietta Ideal 
Quarry, northeast of Castle Hayne, New Hanover County, N.C. 32 
mm in height. 

Top center. Notorhynchus aff . N. serratissimus (Agassiz), 
1 844, UNC 8467, Cooper Marl, upper bed, Giant Portland Quarry, 
Harleyville, South Carolina. 19.8 mm in length. Similar fossils 
occur in the River Bend Formation of North Carolina. 

Top right. Pecten trentensis Harris, 1919b, UNC 12536d, 
Oligocene River Bend Formation, N.C. Department of Transporta- 
tion Quarry, northeast of Pollocksville, Jones County, N.C. 21.2 
mm in height. 



Bottom left. Oxyrhina praecursor (Leriche), 1905, UNC 
8429, Upper Eocene Cross Member of the Santee Limestone, Giant 
Portland Quarry, Harleyville, South Carolina. 25.1 mm in height. 
This species also occurs in the Eocene Castle Hayne Formation of 
North Carolina. 

Bottom center. Rapana gilletti Richards, 1943, UNC 
12526a, Late Oligocene or Early Miocene, Haywood Landing 
Member of the Belgrade Formation, Haywood Landing. 35 mm in 
height. 

Bottom right. Hemipristis serra Agassiz, 1843, UNC 
14231, North Carolina, probably from the Miocene Pungo River 
Formation. 25.5 mm in height. 



25 



CROWDERS MOUNTAIN 
STATE PARK 

Crowders Mountain State Park is in the 
western Piedmont in Gaston County, 6 miles west 
of Gastonia and 8 miles north of the South Carolina 
State line. Interstate 85 passes a few miles north of 
Crowders Mountain. The park was established in 
response to public concern that kyanite mining 
activities might destroy the beauty of the mountain. 



GEOLOGY 

The park is located in the Kings Mountain 
belt of rocks. These rocks are of both sedimentary 
and volcanic origin, and were deposited in a shal- 
low basin or sea over 500 million years ago. They 
were later deeply buried, altered by heat and pres- 
sure (metamorphism) and then tilted on edge. 
Finally, they were exposed at the earth's surface 
through the processes of weathering and erosion. 
The most prominent feature of the state park is 
Crowders Mountain, a monadnock rising 750 feet 
above the surrounding Piedmont plateau. 

The main rock types in the park are quartz- 
ite and phyllite of the Battleground Formation. 
Quartzite is very resistant to weathering because of 
its high quartz content. It forms the park's major 
peaks such as Crowders Mountain and the Pin- 
nacle. In places, the quartzite forms beds up to 600 
feet thick. The quartzite contains crystals of an 
aluminum-rich mineral called kyanite. A close 
look at the quartzite reveals crystals of kyanite in 
radiating clusters and in crystals aligned parallel to 
each other. (// is illegal to collect samples.) 

The phyllite we see in the park contains the 
minerals mica and quartz. In places it contains 
small amounts of kyanite, andalusite, pyrite, and, 
rarely, staurolite. The soil above this rock contains 
many small white mica flakes. 

The Kings Mountain belt is rich in rock and 
mineral deposits that have been mined for feldspar, 
marble, lithium, tin, mica, kyanite, sillimanite, 



Reed Gold 




barite, gold, manganese, and iron. Quartzites such 
as those seen in the park were prospected nearby 
for kyanite and have been mined in South Carolina. 
Kyanite is used in making heat resistant ceramic 
products such as spark plug insulators. 

West of the park, large deposits oi feldspar, 
spodumene (a lithium-bearing mineral), and mica 
are mined. North Carolina annually leads the 
nation in the production of these valuable mineral 
resources. A few miles west of the park was the 
most important gold mine in the district, the Kings 
Mountain Mine. This mine produced as much as 
$1 million in gold prior to 1895. 



TRAILS 

Crowders Trail begins at the park office 
and leads to the top of Crowders Mountain. The 
trail begins in quartz-mica phyllite, which under- 
lies lower elevations in the park. Phyllite is much 
less resistant to weathering than the quartzite. The 
phyllite is not well exposed, but tiny flakes of mica 
in the soil indicate that phyllite is near the surface. 
On the slopes of Crowders Mountain large quartz- 
ite boulders are scattered about. These boulders 
fall from the top of the mountain and moved down 
slope to where we see them now. Many of the 
boulders on the trail to the top of the mountain 
contain kyanite. The kyanite is recognizable as 
white, blade-shaped crystals on the surface of the 
rocks. In some places the crystals weathered out of 
the rock and are scattered along the trail. 



27 



The boulders are cut by flat, straight sur- 
faces ca.\ied joints. Joints are cracks in the rock that 
formed as the rock was deformed by forces deep 
within the earth or during removal of the overlying 
rock mass by erosion. It is usually possible to see 
numerous parallel joints and then other joints at 
different angles. Many of the rocks are also cut by 
very closely spaced parallel cracks that give the 
rock a layered appearance. This pattern is usually 
formed by the parallel alignment of platy minerals 
and is called cleavage. It also formed when the 
rocks were deeply buried and is the result of forces 
that folded and faulted the rocks. 

Near the top of Crowders Mountain, the 
steep cliffs are formed by quartzite. Along the trail 
below the cliffs is weathered quartz-mica phyllite. 
At the top of the mountain are spectacular views of 
the Piedmont. The skyline of Charlotte is to the 
east. Spencer Mountain, visible to the northeast, is 
another peak formed by the same type of quartzite 
as Crowders Mountain. To the southeast is Henry 
Knob, South Carolina, where kyanite was mined 
from the quartzites. 

Cleavage is prominent in most of the rocks 
on top of the mountain. It is very steeply inclined 
and, in a few places, has small folds or contortions 
in the cleavage. Weathering pits are irregularly 




rounded depressions that developed on top of some 
of the boulders. The pits begin where some miner- 
als weather more rapidly than others. Water col- 
lects in the resulting spaces in the rock surface, 
slowly enlarging the depressions, and merging 
them with others. This forms a distinctive pock- 
marked surface. 

Rock Top Trail follows the ridgeline of 
Crowders Mountain. Most of the trail is across 
bare boulders and outcrops of kyanite quartzite. 
Weathering pits are well exposed in a large out- 
crop of quartzite near the top of a ridge. Where the 
trail crosses the road to the radio tower, weathered 
quartz-mica phyllite is exposed. Cleavage, the 
parallel alignment of mica flakes, is almost vertical 
in this rock. Just below the tower, a large quartzite 
boulder contains a quartz vein. The vein is only a 
few inches wide. It probably formed when the 
quartzite was deeply buried and hot silica-rich so- 
lutions filled cracks in the rock. The solution later 
cooled and solidified. 

Pinnacle Trail follows a low ridge to the 
base of the Pinnacle and then up to the peak. 
Kyanite quartzite and many of the other features 
seen on Crowders Mountain are also seen in this 
area. 



CLASSIFICATION OF METAMORPHIC ROCKS 





Texture 


Composition 


Rock Name 


2 

t> 
5 

w 

"to 

s. 

c 
a 
c 
o 
o 

T> 

j5 
.5 
"o 

U- 


Coarse grained; 
grains parallel. 


Feldspar, quartz, mica, 
hornblende, garnet. 


Gneiss 


Medium grained; 
grains parallel. 


Mica, hornblende, talc, 
quartz, garnet, chlorite. 


Schist 


Fine grained; 
grains parallel. 


Mica, quartz, chlorite, 
feldspar. 


Phyllite 


Very finegrained; 
dense, slaty cleavage 


Microscopic flakes of 
mica, quartz, and feldspar 


Slate 


3 

to ^ 


Granular; 
sometimes banded 


Calcite or dolomite 


Marble 


Granular; massive 


Quartz 


Quartzite 



Cleavage in metamorphosed sandstone. 



28 



DUKE POWER STATE PARK 

Duke Power State Park occupies 1,452 
acres in west-central North Carolina. It is approxi- 
mately 10 miles south of Statesville in Iredell 
County. The park is on the north shore of Lake 
Norman, the state's largest man-made lake. The 
lake occupies 32,5 10 acres and 520 miles of shore- 
line when filled to capacity. It was formed by the 
Cowans Ford Dam, whose construction was begun 
in 1959 on the Catawba River. The lake powers 
Duke Power company's hydroelectric generators 
at the dam, and also is a source of cooling water for 
"steam-electric" generators at the coal-powered 
Marshall Steam Station. These two facilities, 
along with the recently completed McGuire Nu- 
clear Station, provide power to a rapidly growing 
section of the Piedmont. 



GEOLOGY 

The park is located near the northern exten- 
sion of a group of rocks called the Kings Mountain 
belt. This belt of rocks extends in a northeasterly 
direction from the South Carolina line for approxi- 
mately 40 miles through Cleveland, Gaston, Lin- 
coln, Catawba, and Iredell Counties. The Kings 
Mountain belt is bordered on the northwest by the 
Inner Piedmont geologic province and to the south- 
east it is bordered by the Charlotte belt. 

The Kings Mountain belt consists of meta- 
morphosed sedimentary and volcanic rocks such 
as quartzite, conglomerate, marble, quartz- sericite 
schist, hornblende gneiss, and biotite gneiss. The 
original sedimentary and volcanic rocks were 
deposited in a shallow basin over 500 million years 
ago. They were later deeply buried, altered by heat 
and pressure, and tilted on edge. Erosion has 
exposed the rocks at the land surface. 

The rocks most often seen in Duke Power 
State Park are quartz-muscovite schist, biotite 
gneiss, granitic gneiss, and amphibolite. These 
rocks are poorly exposed because of deep weather- 
ing typical of most of the Piedmont. The best place 



HICKORY^ 


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to see the rocks is along the lake shore during low 
water levels. A few outcrops are scattered in the 
woods and along small creeks. Normally, the only 
indication of the type of rock beneath the surface is 
small, shiny flakes of mica or small scattered rock 
fragments in the soil. 

One of the best exposed rocks is quartzite, 
which occurs along a ridge 200 feet east of the main 
park entrance. The quartzite is exposed in a line, 
more or less continuously, for over 700 feet. The 
rock is composed primarily of white or colorless 
quartz with small amounts of mica and occasion- 
ally sillimanite. It forms ridges because it is more 
resistant to erosion than the surrounding rocks. 
The rock may have originally formed as a beach 
sand. 



TRAILS 

Swimming Area Trail - This trail follows the 
shoreline of a small peninsula which extends into 
Lake Norman. By following the right fork of the 
trail, the first rocks seen are boulders of biotite 
gneiss. Biotite is a black variety of the mineral 
mica. The rock surface of the boulders has broken 



29 



or peeled off along curved surfaces, a process 
called exfoliation. Farther along, the trail passes 
the earthen dam which separates the small lake 
from Lake Norman. Granite boulders used as rip 
rap here were probably quarried nearby and 
trucked to this site for use in the dam. 

Farther along the trail a boulder of amphi- 
bolite is exposed. Amphibolite is composed pri- 
marily of the iron-rich mineral hornblende. The 
reddish stain on the exterior of the boulder is from 
hornblende weathering to iron oxide, much the 
same way rust forms on a nail. A good exposure of 
granite gneiss is on the east side of the peninsula 
after the trail turns back toward the swimming area. 
This outcrop is elongate parallel to layering in the 
rock. The layering is formed by alternating layers 
of dark- and light-colored minerals. 

At the top of the hill near the picnic tables 
is an almost perfectly round boulder of massive 
granite. This is an example of exfoliation which 



has resulted in the eventual rounding of a boulder. 
When a rounded boulder is formed, the process is 
called spheroidal weathering. This is common in 
rocks that have well developedjoints or fractures. 

Buildings in the swimming area are con- 
structed from quartzite quarried just outside the 
park entrance. Quartzite, composed mostly of 
quartz, is a very hard, weather-resistant rock. A 
small quarry was opened in the rock to provide 
stone for construction in the park. 

The loop trail from the camping area 
crosses biotite gneiss and quartz-sericite schist. 
Schist is a rock composed principally of mica 
flakes aligned parallel to each other. This is easy to 
recognize, even when poorly exposed, because of 
the abundant mica flakes occurring in the soil. 
Biotite gneiss is exposed along the shoreline of the 
lake. The gneiss is broken into elongate fragments 
parallel to layering in the rock. 



Unweathered rock 



Weathered rock (saprolite) 




Spheroidal weathering develops in massive rocks, such as granite, that have regularly spaced joints. Joints act as 
avenues along which water moves. Water slowly dissolves minerals on the rock surface until the rock develops a 
rounded surface. The rock may peel off in layers or shells, much like an onion skin. 



30 



ENO RIVER STATE PARK 

Eno River State Park is in the northern 
Piedmont of North Carolina, approximately 3 
miles northwest of Durham. The park occupies 
1,965 acres along the Eno River in northern Dur- 
ham and Orange Counties. 



GEOLOGY 

The park is in an area known as the Caro- 
lina slate belt. This belt of rocks begins at the 
North Carolina- South Carolina State line at Union 
and Anson counties and trends northeasterly 
through the state to the North Carolina- Virginia 
State line. This belt is composed of interlayered 
volcanic lava flows, pyroclastic rocks (pyro = fire, 
clastic = fragment), and sedimentary rocks. After 
deposition, cooling, and solidification, the vol- 
canic rocks were deeply buried, folded, and 
faulted. At the same time they were changed by 
heat and pressure. This process is called metamor- 
phism. 

The metavolcanic rocks in Eno River State 
Park were intruded by younger molten material 
called magma. The silica-rich magma crystallized 
at depth to form igneous (from the latin "ignis" 
meaning fire) rock called granite. These granitic 
intrusive rocks are now exposed at the earth's 
surface. Rain, snow, ice, and wind sculptured and 
eroded the park terrain and have exposed the 
outcrops of granite we see today. 

Since there is no evidence of ancient vol- 
canic vents, the metamorphosed volcanic rocks 
within Eno River State Park may have erupted 
from faulted areas known as fissures that were ac- 
tive periodically for millions of years. The vol- 
canic rocks were deposited over two geologic time 
periods called Late Proterozoic and Cambrian. 
Volcanic deposition began in late Proterozoic 
time, from 700 to 570 million years ago, and con- 
tinued through the Cambrian period, which began 
570 million years ago and lasted for 70 million 
years. 



Welcome Center 
Kerr Reservoir State Recreation Area 



Historic 

Hillsborough Eno River 




Eno River is unique to this part of the Pied- 
mont because of the numerous rapids in the areas 
underlain by metavolcanic rocks. These rocks are 
more resistant to erosion than the metamorphosed 
sedimentary and igneous rocks, and they form 
scenic white-water rapids. Rapids provide excit- 
ing canoe trips along this meandering, cascading 
river. 



TRAILS AND ACCESS AREAS 

Cates Ford Access Area - The predomi- 
nant rock types that can be seen in this area are 
metavolcanic flow rocks, pyroclastic rocks, and 
granitic rocks. 

The rock types at Cates Falls are pyroclas- 
tic rocks called tuff breccia (breccia is a rock that 
contains angular rock fragments). Interlayered 
with the pyroclastic rock is a volcanic mudflow 
that geologists call a lahar. A lahar is a volcanic 
mudflow that contains unsorted, randomly ori- 
ented volcanic clasts or debris, ranging in size from 
less than an inch to blocks over 3 feet in length. 
These rock fragments also vary in composition and 
color, so that in outcrop, the lahar has a mottled 



31 



gray appearance. Imagine volcanic debris lying on 
the flanks of a fissure or vent becoming saturated 
with as much as 60 percent water that condensed 
from steam from the fissure. This water-saturated 
volcanic debris begins to move downslope away 
from the fissure, following valleys or stream chan- 
nels. The lahar can be viewed in outcrop where it 
is crossed by the Eno River at Cates Falls. The 
lahar forms the falls. Blocks over two feet in length 
can be seen in this easily-reached outcrop. 
Mudflows similar to this formed on the slopes of 
Mount St. Helens during the 1980 eruptions. 

Cole Mill Access Area - A metavolcanic 
rhyolite lava flow is on the northwest side of Eno 
River along Bobbitt Hole Trail. The flow is a 
dense, light gray silica-rich rock that has a knobby 
texture on weathered surfaces. These knobs are 
formed by marble-size spheres called spherulites. 
They are composed of crystal clusters of the min- 
erals quartz and feldspar that radiate outward from 
a center or nucleus. These spherulites range in size 
from less than one-tenth of an inch to over two 
inches in diameter. They formed as the glassy lava 
flows cooled and solidified. Because of the radiat- 
ing form and shape of the spherulites, some early 
geologists identified them as silica-rich coral fos- 
sils of marine origin. But in 1899, a geologist 
named Joseph Diller correctly identified them as 
spherulites. 

Cabes Land Loop Trail, 1.5 miles in 
length, provides the park visitor a hilly terrain for 
viewing the few geologic features exposed along 
the trail. Your hike begins in a red clay soil that 
developed from the underlying igneous intrusive 
granite. As the trail continues in a northerly direc- 
tion toward the Eno River, a close look reveals that 
the granite weathered to produce saprolite. Sapro- 
lite is a term used to define a soft, earthy decom- 
posed rock formed in place by chemical weather- 
ing. Large granite outcrops are absent along the 
hiking trail, but residual granite boulders are in the 
wooded areas near the river. 



A contact between granite and metavol- 
canic rock occurs along the Eno River. This 
metavolcanic rock is a pyroclastic or fragmental 
volcanic rock called tuff. The tuff formed from 
debris that was blown from a fissure, settled to the 
ground, and solidified. The quartz and feldspar 
crystals visible in the tuff formed, or crystallized, 
as the pyroclastic rock cooled and solidified. At 
this outcrop, the rock trends in a northeasterly 
direction, and forms white-water rapids where it 
crosses Eno River. This was the old dam site for 
Cabe's Mill. The wooded island visible just up- 
stream was formed as the dam stopped the flow of 
the river and impounded the water for Cabe's Mill. 
Sediment carried in suspension settled out into the 
river channel. Over the years, this bedded sedi- 
mentary deposit extended from the base of the dam 
to several hundreds of feet upstream. When the 
dam was destroyed, the river began to flow and 
entrench itself on each side of the sediment mass, 
forming the island that exists today. 




Pyroclastic rock. 



32 



HANGING ROCK STATE PARK 

Hanging Rock State Park is located in 
Stokes County, approximately 32 miles north of 
Winston-Salem and 4 miles southwest of Danbury . 
The 6,000 acre park is in the northwestern portion 
of the Piedmont physiographic province. 



GEOLOGY 

The park lies within an area known geol- 
ogically as the Sauratown Mountains anticli- 
norium. The anticlinorium is an area where the 
rocks were arched upward. About one billion 
years ago silt, sand, and clay washed into a sea 
environment. Layer upon layer of sediment accu- 
mulated and was later changed by heat and pres- 
sure (metamorphism) to the metamorphic rocks 
we see today. Volcanic rocks were deposited in 
some parts of the basin. Approximately 700 mil- 
lion years ago hot molten rock (magma) invaded 
the sediments and then cooled to form granite. 
Gradual uplift and erosion exposed the rocks at the 





EIDSVILLE 



North Carolina 
Zoological 
Park 

eagrove 



surface, where the action of erosion and weather- 
ing carved the rocks into their present appearance. 

Features of the original shallow-water 
environment are now evident in the quartzite that 
forms the peaks in Hanging Rock State Park. The 
quartzite (metamorphosed sandstone) contains 
horizontal bedding, and in places, cross-bedding, 
where quartzite beds are aligned at an angle, one to 
another. Cross-bedding forms where currents or 
winds carrying sand change direction. Layers of 
sand accumulate on top of each other oriented at 
different angles. Cross-bedding in the park formed 
in a nearshore or beach environment. 

The main geologic features in the park are 
formed by outcrops of quartzite. Because the 200- 
foot thick quartzite is more resistant to erosion, this 
layer of rock formed a protective cover that now 
caps and supports the scenic ridges and knobs of 
Moore's Knob, Moore's Wall, Cook's Wall, 
Devil's Chimney, Wolf Rock, and Hanging Rock. 
The quartzite also forms the ridge line of the 
Sauratown Mountains. The Sauratown Mountains 
are sometimes called "the mountains away from 
the mountains" because of their close proximity to 
the Blue Ridge Mountains, only 27 miles north- 
west, across the valley of the Dan River. Pilot 
Mountain is also formed by the quartzite. 



Hanging Rock. 



33 



TRAILS 

Hidden Falls Trail - This steeply descend- 
ing, winding trail is only 0.4 mile long, but its short 
length is deceiving because of the unique outcrops. 
Light-gray to tan, sparkling micaceous quartzite 
beds form a step-like trail that leads to a cascading 
waterfall, hidden from view until the last turn of the 
trail. Picturesque Hidden Falls is a cascading 
waterfall that plunges over a bedded quartzite 
scarp and then cascades over the quartzite beds at 
its base. The water then flows into a stream channel 
filled with quartzite boulders and large blocks that 
were eroded from the face of Hidden Falls scarp. 
These blocks were broken away by running water 
and ice wedging along the flat surface of the 
quartzite. 

After retracing the path only a short dis- 
tance, it is possible to continue to follow this trail 
to the most appropriately named Window Falls. 
Just before the descent to view the falls, there is a 
large quartzite outcrop on the right. The white 
quartz veins were injected along the horizontal 
bedding planes of the quartzite and lie parallel to 
each other. This quartz was forced into the quartz- 
ite millions of years ago, the last time the rock was 
deformed. Hydrothermal (hot water) solutions 



were injected under pressure along the horizontal 
bedding planes of the quartzite. Upon cooling, 
silica precipitated out of solution and solidified as 
quartz veins. The "window" probably developed 
as rain water and creek water filled fractures 
(joints) and bedding surfaces in the quartzite. 
Then, because of freezing and thawing, the quartz- 
ite blocks were pushed apart, forming a hole or 
"window". By carefully looking upstream from 
the ledge of the "window", it is possible to see 
Window Falls as it cascades and falls from the face 
of the bedded quartzite scarp. 

Lake Trail - A trail extends from the 
Family Camping Area, winding down to a 12 acre 
manmade lake. Several geologic features occur 
along this densely wooded trail. Three hundred to 
four hundred feet down trail, an artesian spring 
flows across the trail. Groundwater, under artesian 
pressure, flows from joints and fractures within the 
underlying mica-rich quartzite. Further down trail, 
a large rounded outcrop of quartzite is on the south 
side of the trail. The curved appearance or spheri- 
cal shape forms as fractures, joints, and horizontal 
bedding planes within the quartzite begin to 
weather concentrically, forming rounded surfaces 
where angular surfaces once existed. This weath- 
ering process is known as spheroidal weathering. 




Topographic map of a portion of the Hanging Rock 7.5 minute quadrangle. The numbered lines are contour lines. 
Each point along a line has the same elevation above sea level. The land surface is steepest where contours are closest. 



34 



PIEDMONT RESERVOIRS-STATE 
RECREATION AREAS 

In the eastern Piedmont, the Division of 
Parks and Recreation manages Recreation Areas 
at three large reservoirs: Falls Lake, Jordan Lake, 
and Kerr Lake. These recreation areas provide a 
variety of recreational activities including boating, 
camping, fishing, hiking, hunting, picnicking, 
swimming, and white water canoeing. Rocks 
exposed along the shoreline of the reservoirs pro- 
vide the opportunity to observe the varied geology 
of the eastern Piedmont. 

The reservoirs are located in the eastern 
Piedmont physiographic province. They are in 
three major geologic areas, the Carolina slate belt, 
the Raleigh belt, and the Durham Triassic basin. 
All major rock types (igneous, metamorphic, and 
sedimentary) are represented in the recreation ar- 
eas. Rocks in this portion of the Piedmont formed 
from sediments deposited in an inland sea or basin 
between 520 and 800 million years ago. Sediments 
were washed into the sea and, at the same time, 
nearby volcanoes ejected volcanic rocks and de- 
bris into the basin. These rocks were later deeply 
buried and altered by heat and pressure 
(metamorphism)to form the metamorphic rocks, 
gneiss and schist, we see today. Approximately 
240 to 435 million years ago, hot molten rock, 
magma, intruded the sedimentary and volcanic 
rocks and solidified to form igneous intrusive 
rocks such as granite. Some of the intrusive rocks 
were also altered by metamorphism. 

During the Late Triassic Period, about 
220 million years ago, strong forces within the 
earth's crust pulled apart rocks along the east coast 
of the United States. This was the beginning of the 
formation of the Atlantic Ocean as sea floor 
spreading and continental drift separated the con- 
tinents. These forces caused some large areas to 
drop down in relation to surrounding areas that 
were mountainous at that time. Long, narrow 
basins were formed in the crystalline rocks along 
the east coast, including North Carolina. As rivers 
began to wash clay, sand, and cobbles into the 



Welcome Center 

Kerr Reservoir State Recreation Area « 




narrow troughs, layer after layer of clay, sand, and 
gravel gradually accumulated. Lakes also formed 
in the basins. Thousands of feet of sedimentary 
rocks now fill the Triassic basins. Erosion for 
millions of years has exposed both the metamor- 
phic rocks and the Triassic sedimentary rocks at the 
earth's surface. 

Portions of Falls Lake and Jordan Lake lie 
within the Durham Triassic basin. A major fault, 
the Jonesboro fault, forms the eastern boundary of 
the basin. This fault is the break in the earth's crust 
where rock to the west dropped down. It separates 
unmetamorphosed Triassic sedimentary rocks 
from metamorphosed rocks of the Piedmont. Rock 
exposures in the recreation areas are usually best 
exposed along the lake shore during periods of low 
water level. 



FALLS LAKE RECREATION AREA 

Falls Lake is located in Durham, Granville, 
and Wake Counties about 12 miles north of 
Raleigh and 5 miles east of Durham. The lake 
extends for about 22 miles up the Neuse River from 
the town of Falls in northern Wake County. It 
covers 12,490 acres when contained at its conser- 



35 



vation pool level of 250.1 feet above mean sea 
level. Recreational areas and trails are being estab- 
lished through a series of multi-year projects. A 
trail along the south shore of the lake will be a part 
of the Mountains-to-the-Sea Trail project. This 
project will eventually result in a hiking trail 
extending from the mountains to the coast. 

Falls Lake lies within two geologic prov- 
inces, the Raleigh belt and the Durham Triassic 
basin. All three major classifications of rock, 
igneous, metamorphic, and sedimentary, are in 
the recreational area. The northwest half of the lake 
lies within the Durham Traissic basin. Rock types 
include fanglomerate, conglomerate, and finer 
grained rocks ranging from sandstone to 
mudstone. Fanglomerate is a very coarse rock 
composed of large angular fragments of other 
rocks. This rock formed along the eastern bound- 
ary fault (Jonesboro fault) as streams washed de- 
bris down the steep slopes and formed alluvial fans. 
Also along this narrow zone is conglomerate 
which contains rounded rock fragments. The 
conglomerate represents material that was depos- 
ited by streams that smoothed the large rock frag- 
ments as they were carried downstream. The 
sandstone and mudstone were deposited away 
from the steep border of the basin where the 
streams were moving more slowly. 

East of the Durham Triassic basin are 
metamorphic and igneous intrusive rocks of the 
Raleigh belt. The metamorphic rocks are both 
light-colored (felsic, quartz-rich) and dark-colored 
(mafic, quartz-poor) gneiss and schist. Dark-col- 
ored igneous intrusive rocks are also scattered in 
the area. The igneous rocks include diorite, 
gabbro, and altered ultramafic (iron-rich) rock. 
Ultramafic rock includes soapstone, and many 
years ago this was quarried nearby for use as 
building stone. 



B. EVERETT JORDAN LAKE 
RECREATION AREA 

B. Everett Jordan Lake is approximately 25 
miles west of Raleigh. It is formed by an earth and 



rock fill dam built by the U.S. Army Corps of 
Engineers to impound water on the Haw River and 
New Hope Creek. The project serves multiple 
purposes of flood control, water supply, water 
quality control, outdoor recreation, and fish and 
wildlife conservation. The Division of Parks and 
Recreation operates numerous recreation areas 
along the 150 miles of shoreline. 

The lake is almost entirely within the Dur- 
ham Triassic basin. Sedimentary rocks exposed 
occasionally along the shoreline are sandstone, 
mudstone, and conglomerate. Triassic rocks yield 
important quantities of clay for use in the brick and 
tile industry. Mines nearby help North Carolina 
annually lead the nation in brick production. Far- 
ther south in the Sanford Triassic basin, coal was 
mined prior to 1953. No coal has been found in the 
Durham Triassic basin. Oil test wells show small 
amounts of oil and gas, but commercial amounts 
have not been found. Felsic volcanic rocks of the 
Carolina slate belt occur in the southern lake area. 



KERR LAKE RECREATION AREA 

Kerr Lake Recreation Area, located in 
northeastern Warren and northwestern Vance 
counties, is in the northeastern North Carolina 
Piedmont adjacent to the North Carolina - Virginia 
State line. Gently rounded hills with moderate 
slopes form the shore line of this 1 6,300 acre man- 
made lake. Kerr Lake's seven recreational areas 
are on peninsulas, some of which protrude into 
Kerr Lake for over one mile. These recreation 
areas are located between 5 and 25 miles north of 
Henderson, North Carolina. 

The Kerr Lake Recreational Area is located 
in a geologic belt known as the Raleigh belt, an 
area composed primarily of metamorphic rocks 
and igneous intrusive rocks. The main metamor- 
phic rock types at Kimball Point and County Line 
Recreation Areas are interlayered biotite gneiss, 
felsic gneiss, and hornblende gneiss. Gneiss is an 
old German word that originated among the early 
miners in the Saxony. It was loosely used to 



36 



include all coarse-grained banded rocks. 

Biotite gneiss is more abundant than the 
other two rock types, and is composed of the 
minerals biotite mica, a black mica that occurs as 
thin tabular hexagonal crystal forms; muscovite 
mica, a colorless to light-green mineral; quartz; 
and two varieties of feldspar minerals, microcline 
and plagioclase. In outcrop, the biotite gneiss has 
a dark and light banded or layered appearance. The 
darker bands or layers range in thickness from less 
than an inch to over four feet; however, most are 
only a few inches thick. This banded appearance is 
caused by variations in the amount of biotite mica 
from layer to layer. 

The felsic gneiss is light in color, uniform 
in appearance, and contains the minerals musco- 




Aeromagnetic map showing the trend of the Nutbush 
Creek mylonite zone (NCMZ). The numbered lines are 
contours that indicate the magnetic intensity in 
gammas along the line. 



vite mica, quartz, and plagioclase feldspar. The 
hornblende gneiss is not as common in outcrop as 
the two previously mentioned gneisses. The physi- 
cal appearance of this rock type is unusual because 
the black hornblende mineral and feldspar are 
aligned parallel to each other giving this rock a 
"striped" appearance. 

A zone of deformed or sheared rock, called 
the Nutbush Creek mylonite zone, is exposed at 
Henderson Point and trends in a southwesterly di- 
rection through Bullocksville and Satterwhite 
Point Recreation Areas. This relatively narrow, 
steeply inclined fault zone separates the Raleigh 
belt from the Carolina slate belt. Mica gneiss east 
of the fault zone moved both vertically and hori- 
zontally in relationship to granite west of the zone. 
Rocks within the zone have been deformed into 
new rocks called phyllonite and mylonite. The 
original minerals were crushed, broken, and 
stretched out into thin layers. Some of the rock 
surfaces contain small mica flakes that give the 
rock a shiny appearance. 

The fault zone stands out as nearly a 
straight line on aerial photographs. Creeks, such 
as Nutbush Creek, follow the trace of the zone be- 
cause, in some places, rocks in the zone are less 
resistant to erosion. In other places, the rocks are 
harder than the surrounding rocks and form long 
ridges. By measuring the magnetic properties of 
rocks in this area, the zone can also be traced on 
aeromagnetic maps. (Refer to figure in the oppo- 
site column.) 

West of the Nutbush Creek mylonite zone, 
the metamorphic rocks were intruded by molten 
rock called magma that crystallized at depth to 
form granite. Some of the granite was emplaced 
650 to 520 million years ago. The granites can be 
seen in outcrop at Bullocksville and Satterwhite 
Point Recreation Areas. 



37 



MEDOC MOUNTAIN STATE PARK 



Medoc Mountain State Park is in south- 
western Halifax County 27 miles northeast of 
Louisburg and 18 miles southwest of Roanoke 
Rapids. The park is located along the fall line, a 
narrow zone which marks the boundary between 
hard, resistant rocks of the Piedmont and softer 
rocks of the Coastal Plain. The Piedmont rocks 
here are part of the Eastern slate belt and were 
formed when volcanic and sedimentary materials 
were deposited some 500 to 800 million years ago. 
These materials were deeply buried and changed 
by heat and pressure to form metamorphic rocks 
such as gneiss, schist, metavolcanic rock, or 
metasedimentary rock. The Piedmont rocks also 
include masses of granite which forced their way 
into the metamorphic rocks from below as molten 
masses {magma). The Piedmont rocks were very 
slowly lifted up and then eroded by the action of 
rivers and weathering processes to form the present 
day land surface. 

In the northeastern Piedmont, many of the 
ridge tops were flattened by erosion and capped 
with thin layers of sand and gravel. The sand and 
gravel layers are much younger than the underly- 
ing Piedmont rocks, and are probably "only" a few 
million years old. They were laid down and left 
behind by streams and rivers as they cut down into 
the Piedmont surface. 

The rolling topography of the Piedmont 
gradually gives way to the flat Coastal Plain just 
east of the Park area. The Coastal Plain is made of 
layer upon layer of sedimentary deposits such as 
sand, clay, marl, and limestone that range in age 
from tens of thousands of years to over 100 million 
years. These sediments were laid down by ancient 
rivers flowing across the Coastal Plain and in the 
shallow seas that formed as the ocean moved back 
and forth across the continental margin. Such 
changes in sea level resulted from gradual sinking 
of the land and from freezing and thawing of the 
Earth's polar ice caps. Marine deposits are found 
as far as 200 miles inland from our present day 





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coastline and at elevations several hundred feet 
above present day sea level. 

The Coastal Plain sediments form a wedge- 
shaped mass that overlies crystalline rocks like 
those of the Piedmont. This wedge thickens from 
a "feather edge" at the fall line to a maximum 
thickness of nearly 10,000 feet at Cape Hatteras. 



GEOLOGY 

Medoc Mountain and adjacent ridge tops 
are underlain by a granite mass that is about 300 
million years old. The granite is composed of the 
minerals feldspar, quartz, and mica. Quartz veins 
are found in the granite and the surrounding meta- 
morphic rocks. Quartz veins are not found in the 
Coastal Plain sedimentary rocks; so, we know that 
the veins formed before the sediments but later 
than the Piedmont rocks. The veins are sheet-like 
bodies that moved as hot liquids into fractures and 
zones of weakness in the surrounding rocks. As the 
liquid cooled, silica precipitated out and formed 
quartz veins. Quartz is very resistant to chemical 
decay or weathering. The plentiful quartz lying on 
the surface of the ground, referred to as float, 



38 



indicates that quartz veins are just beneath the 
surface. 

The Medoc Mountain area is significant to 
geologists because it is the site of a metallic mineral 
occurrence. Molybdenite (MoS 2 ), a mineral that 
contains molybdenum, was found at this site in 
1936. Molybdenum is a metal valued as an alloy 
because of its high strength and low weight prop- 
erties. The deposit was explored off and on by 
private firms and government agencies until about 
1970. The United States Bureau of Mines con- 
ducted a sampling and core drilling investigation 
during and after World War II as part of a program 
to discover and evaluate strategic minerals. Al- 
though this is one of the largest molybdenum 
deposits known in the southeastern United States, 
it is small compared to deposits mined in the 
western United States and was never mined. 

Molybdenum occurs in the Park as the 
mineral molybdenite (MoS 2 ), a steel blue or silver- 
colored flaky mineral found in some quartz veins 
and in portions of the granite. The brass colored 
mineral pyrite (FeS 2 ), or fools gold, is often found 
with molybdenite. 



TRAILS 

Summit Trail - This 3 mile loop trail origi- 
nates at the Park Office and includes Little Fishing 
Creek and the "peak" of Medoc Mountain. 




Contact 



4| 



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— Jf - : 

A nearly vertical diabase dike cross-cuts granite in a 
rock quarry. The dike is 10 feet wide. 

Geologists measure the magnetic intensity 
of rocks in order to study rocks that cannot be seen 
at the Earth's surface. Because diabase contains a 
relatively large amount of the magnetic mineral 
magnetite, it is usually seen as a magnetic "high" on 
magnetic maps. This enables geologists to map 
rocks even though the rocks are not visible at the 
surface. Magnetic maps are also useful in mineral 
exploration and interpreting the structure of rocks. 



Quartz float can be seen along the trail as 
it winds down the slope to the creek. As the slope 
becomes steeper, blocks of dark colored, fine- 
grained rock are scattered along the surface of the 
trail and in the adjacent woods. This rock is a type 
of igneous rock called diabase. The blocks can be 
traced in a straight line and indicate that the rock is 
a sheet-like, vertical feature a few feet wide known 
as a dike. Diabase dikes intruded rocks in the 
Piedmont approximately 200 million years ago 
when North America and Africa drifted apart to 
form the Atlantic Ocean. 



Farther along on Little Fishing Creek, a 
large outcrop of granite rises adjacent to the trail. 
The granite is cut by numerous quartz veins. Mo- 
lybdenite and pyrite are visible in a few of the 
veins. Look for areas where the quartz has a 
yellowish stain on its surface. The stain is an oxide 
or weathering by-product of the molybdenite. The 
reddish coating on much of the outcrop is similarly 
formed by the weathering of pyrite and other 
minerals containing iron. 

Near the base of Medoc Mountain, red- 
stained quartz float is abundant. Some of the quartz 



39 



has a honeycomb texture. The open spaces result 
from the weathering of pyrite that once filled the 
spaces. The size of the quartz boulders along this 
segment of the trail, and along the road leading 
south from the peak, indicate that some of the veins 
may be as large as several feet thick. 

Dam Site Loop - The Dam Site Loop is a 1 - 
mile long trail that follows Little Fishing Creek a 
short distance upstream from the sharp bend. 
Along this trail, Little Fishing Creek bends sharply 
where the creek encounters the granite that forms 
Medoc Mountain. The granite, reinforced by the 
many quartz veins, deflected the stream from its 
easterly course to one that is southerly along the 
western edge of the granite. 

Where the tributary enters Little Fishing 
Creek a mound of gravel, called a gravel bar, has 
built up near the north bank of Little Fishing Creek. 
Gravel bars form in streams and rivers where the 
water slows down and the water flow is too weak to 
carry the sand and gravel. This commonly occurs 
on the inside of bends or where a tributary enters 
a larger stream. 

Bluff Trail - The Bluff Trail is a 3-mile 
long trail that originates at the picnic shelter on the 
east side of Little Fishing Creek. Where the trail 
climbs the bluff on Little Fishing Creek, there are 
good exposures of metavolcanic rock. In places 
along the top of the bluff, soft, flaky material lies on 
the surface. The flaky material is float from a 
mudstone that is interbedded with the metavol- 
canic rock. Both types of rock are exposed at the 
south end of the bluff where the trail descends back 
to river level. The outcrop here is also cut by a few 
quartz veins. Along the hilltops, rounded pebbles 
and cobbles of quartz are on the surface. The 
cobbles and pebbles are from a gravel deposit that 
caps the hill crossed by the trail. The pebbles and 
cobbles along the trail have very gradually moved 



down the slope by a process known as slope wash. 
During this process gravity slowly moves the 
cobbles down hill as erosion washes away fine- 
grained material around the cobbles. 

Stream Trail - The Stream Trail (3 miles 
long) originates at the picnic area. Rock exposures 
are difficult to find along the Stream Trail. This is 
because the bedrock was cut away by the erosive 
action of Little Fishing Creek, and silt, sand, and 
clay were deposited in its place. One bedrock 
exposure is in a ravine in the beginning portion of 
the trail. The outcrop is of metavolcanic rock 
which has broken or fractured along planes called 
joints. Note the parallel nature of the joints. There 
are two main directions of jointing. One direction 
is to the northeast and the other direction is to the 
northwest. By studying measurements of the joint 
directions, geologists are able to understand the 
forces that caused the rock to fracture. This helps 
them interpret the geologic history of the area. 




A vein cuts across folds in gneiss, indicating that the 
folding occurred before the vein formed. 



40 



MORROW MOUNTAIN STATE PARK 

Morrow Mountain State Park is in the 
south-central Piedmont, approximately 5 miles 
east of Albemarle in eastern Stanly County. It is on 
the western edge of the Uwharrie Mountains, a low 
range of hills in Montgomery, Randolph, and 
Stanly Counties. The Yadkin River forms the 
northern park boundary, and joins with the Uwhar- 
rie River to form the Pee Dee River. The Pee Dee 
River and Lake Tillery form the eastern park 
boundary. Elevations in this 4,641 acre park range 
from a maximum of 936 feet on Morrow Mountain 
to a minimum of 280 feet along the Pee Dee River. 



GEOLOGY 

Morrow Mountain State Park lies within 
the Carolina slate belt, a belt of slighdy metamor- 
phosed volcanic and sedimentary rocks that 
extends from central Georgia to central Virginia. 
Approximately 600 million years ago this area was 
part of a chain of volcanic islands surrounded by a 
shallow sea. Today, we see only the rocks remain- 
ing from the hot volcanic eruptions and the layers 
of sediment deposited in the sea. At the end of the 
volcanic activity, the layers of ash, lava, and sedi- 
ment were deeply buried, folded, tilted on edge, 
and, finally, exposed at the earth's surface. The 
harder volcanic rocks eroded slowly and form the 
mountain peaks in this area and in most of the 
Uwharrie Mountains. The softer sedimentary 
rocks weathered more easily and underlie many 
stream valleys. 

Three principal rock types are recognizable 
in the park. These are rhyolite, basalt, and 
argillite. Rhyolite is a very hard, dark gray, vol- 
canic rock underlying most of the ridges and hills. 
It was once thought that this rock formed a cap on 
the hilltops, but geologists now know that the rock 
is interbedded with the surrounding rocks. The 
rhyolite usually contains small feldspar crystals 
and frequently has wavy flow lines created as the 
hot lava and ash flowed from a fissure or down the 
slope of a volcano. 




Welcome [Mint 
Center. I Museu 
of Art 



"Listen And 
Remember v 
Outdoor Drama (OUI 



Basalt is a dark green to greenish-gray rock 
that is less resistant to erosion than rhyolite. It 
frequently occurs as rounded boulders scattered 
over the ground. Basalt is a magnesium- and iron- 
rich rock, whereas rhyolite contains very little 
magnesium and iron. Argillite, or mudstone, is a 
gray rock where it is fresh, weathering to a brown 
color. It has the appearance of slate but breaks into 
small chips or blocks. Thin parallel lines or layers 
in the rock represent bedding planes — layers of 
mud and silt that were deposited in a shallow sea. 
The rock is not resistant to weathering, and is 
usually found in lower elevations and along creeks. 

Morrow Mountain State Park is in the heart 
of what was once a major gold-mining area. The 
first authenticated discovery of gold in North 
America was in 1799 at the Reed Mine in Cabarrus 
County, only 25 miles west of here. Gold mining 
soon spread to nearby counties, and, until 1828, 
North Carolina was the only producer of gold in the 
United States. Mines in the Carolina slate belt were 
an important part of this production. Although 
gold has not been produced in recent years, it is 
possible to pan gold from the Cotton Patch Mine 
north of Albemarle and in the Uwharrie National 
Forest east of Lake Tillery. (Check with a park 
ranger prior to panning in the National Forest.) The 
possibility of new discoveries continues to lure 
gold-exploration companies into the area. 

Indians occupied this area over 10,000 
years ago and established camps for hunting and 



41 



fishing. Because of its hardness, the rhyolite was 
used extensively in making stone tools. Indian 
tribes from other areas came to the Uwharrie 
Mountains to obtain rhyolite for making tools. 
These tools are commonly found many miles from 
the slate belt. This indicates that the Indians cov- 
ered large areas in search of game, or came to this 
area to obtain raw materials for tools. 



TRAILS 



was part of a quartz vein. A vein is a sheet-like 
body which extends down into the ground hun- 
dreds or thousands of feet and can be traced in an 
almost straight line along the earth's surface. 
Quartz is very resistant to erosion and remains after 
the rocks around it have eroded away. Fractures in 
quartz veins provide good avenues for the move- 
ment of water and are frequently useful sites for 
locating water wells. In some portions of the state, 
gold was found in quartz veins similar to this one. 
This quartz vein is barren of gold. 



Trails in the park provide an excellent 
opportunity to observe the major rock types. Many 
of the trails begin in lower elevations, where argil- 
lite or basalt is exposed, and continue across the 
hilltops, where rhyolite is exposed. Some rock 
types have sedimentary or volcanic features that 
can be seen in individual outcrops and rock frag- 
ments. The top of Morrow Mountain is the most 
easily accessible place to view the rhyolite. Frag- 
ments of the rock are scattered over the ground. 
Argillite is common in the picnic area and in the 
small quarry nearby. Three trails are described 
here. 

Fall Mountain Trail - The trail begins in 
the flat floodplain of the Yadkin River. A 
floodplain consists of loose sand and gravel adja- 
cent to a creek or river which floods periodically. 
Dams on the Pee Dee and Yadkin Rivers help 
prevent floods in this area. 

The trail begins a gradual climb until it 
finally reaches the summit of Fall Mountain. In the 
lower elevations the trail passes through areas 
underlain by argillite. Outcrops are not abundant 
here, but small chips or fragments of tan and brown 
argillite are common on the ground surface. Ge- 
ologists refer to these rocks as float because they 
are suspended on the top of the soil. In areas where 
outcrops are absent, they give good indications of 
the rocks beneath the surface. 

Near the crest of the first low knob, frag- 
ments of milky white quartz are scattered over the 
ground surface. This quartz, also "float" material, 



Near the top of Fall Mountain, fragments of 
rhyolite become abundant on the ground. This is 
the hard, dark-gray volcanic rock found on top of 
the higher peaks in the park. On the trail down to 
the Yadkin River, white, milky quartz "float" be- 
comes mixed with the rhyolite. This indicates that 
a quartz vein is just beneath the surface. Near the 
bottom of the slope, argillite is exposed. 

Near the Falls Dam, hard gray and black 
rhyolite contains many small, white feldspar crys- 
tals. This rock is similar to the rhyolite found on top 
of Fall Mountain. Because it is so hard, it forms 
rapids in the river. The dam is operated by Alcoa 
and provides power to run the aluminum plant. 
Approximately 1.3 miles downstream, the Uwhar- 
rie River joins the Yadkin River and the two 
become the Pee Dee River. A one-mile section of 
the Yadkin River above the dam was once referred 
to as the Narrows. The riverprovided a spectacular 
scene as it narrowed from a width of 1,000 feet 
down to a width of 60 feet. Total fall of the river 
from the head of the Narrows to the mOuth of the 
Uwharrie River was 91 feet. An 1899 publication 
on waterpower in North Carolina describes the 
Narrows as "one of the most wonderful spots that 
can be found in the south." 

As the trail continues along the river, it 
passes through argillite and then into basalt. A 
large outcrop of basalt forms rounded boulders 
along the river bank. The basalt has broken along 
fracture surfaces. Bedded rhyolite is exposed 
beyond the basalt. Thin parallel lines in the rhy- 
olite are bedding planes formed by layers of vol- 



42 



canic ash that were deposited on top of one another. 

Quarry Trail - The quarry trail makes a 
loop from the picnic area to a small quarry. The 
trail provides an opportunity to view good expo- 
sures of argillite. Stone from the quarry was used 
in constructing many bridges, walls, and buildings 
in the park. 

The quarry is a good site for observing 
bedding in the argillite. The bedding is inclined at 
a steep angle, indicating that the rock has been 
tilted from its original horizontal position. Frac- 
tures developed parallel to the bedding planes and 
also at angles to it. The size of trees growing in the 
quarry floor gives an indication of how long it has 
been since this abandoned quarry was operated. 

Sugarloaf Mountain Trail - The trail 
passes through all rock types occurring in the park. 
Near the parking area, rounded boulders of basalt 
and rhyolite are exposed. Farther along the trail, 
white, milky quartz boulders are scattered on the 



surface. The quartz is very resistant and underlies 
a low knob. These boulders have been left behind 
as the surrounding rocks weathered away from a 
quartz vein. The trend of a quartz vein can usually 
be followed by tracing the quartz "float" on top of 
the ground. 

As the trail ascends, it gradually passes into 
the hard, light gray rhyolite. After the trail crosses 
the road to Morrow Mountain, boulders of rhyolite 
breccia are visible. These boulders contain angu- 
lar rock fragments that probably formed as the par- 
tially solid lava flowed and broke into fragments. 

Near the top of the mountain, the rhyolite 
has a banded appearance. These wavy layers are 
flow bands that formed as the hot rock moved. 
They look similar to bedding planes but are more 
undulating in appearance. They are more visible 
on weathered surfaces than on fresh surfaces. As 
the trail descends the east side of the mountain, 
look closely near the base of the mountain for the 
contact between rhyolite and argillite. 




The "Narrows" prior to construction of the Falls Dam. (About 1899) 



43 



PILOT MOUNTAIN STATE PARK 

Pilot Mountain State Park is in Surry 
County, 24 miles north of Winston-Salem. It is 
easily reached from U.S. highway 52, the most 
direct and widely-used route to the park. The 3,768 
acre park is situated in the northwestern portion of 
the Piedmont physiographic province and lies in 
the Sauratown Mountain range. 



GEOLOGY 

The park lies within an area known geol- 
ogically as the Sauratown Mountains anticli- 
norium. An anticlinorium is an area where the 
rocks were arched upward. Rocks in this area were 
formed approximately one billion years ago when 
mud, silt, sand, and clay washed into a sea environ- 
ment. Layer upon layer of sediment accumulated 
and was later changed by heat and pressure (meta- 
morphism) to the metamorphic rocks visible to- 
day. Volcanic rocks were deposited in some parts 
of the basin. Approximately 700 million years ago 
hot molten rock (magma) invaded the sediments 
and then cooled to form granite. Pressures within 
the earth pushed the rocks to the surface where the 
action of erosion and weathering carved the rocks 
into their present appearance. 

Features of the original shallow-water 
environment are now evident in the quartzite that 
forms the peaks in Pilot Mountain State Park. The 
quartzite (metamorphosed sandstone) contains 
horizontal bedding, and in places, cross-bedding, 
where quartzite beds are aligned at an angle to each 
other. Cross-bedding forms where currents carry- 
ing sand in shallow water change direction or 
where wind direction changes on a beach. Layers 
of sand accumulate on top of each other oriented at 
different angles. Bedding of this type formed in a 
nearshore or beach environment. 

When deformation of the rocks ceased, the 
folded rocks and surrounding terrain were then 
sculptured by erosion to their present outcrop 
forms. Water in the form of rain, snow, and ice 




North Carolina 
Zoological 
Park 

Seagrove 



began to degrade and remove the less resistant 
gneiss and schist, channeling these sediments into 
streams and rivers that transported and deposited 
them further into the Piedmont. Because the over- 
lying 200-foot thick quartzite is more resistant to 
the effects of erosion, this layer of rock formed a 
protective cover that now caps and supports Pilot 
Mountain State Park. The quartzite also forms the 
ridge line of the Sauratown Mountains, sometimes 
called the mountains away from the mountains 
because of their close proximity to the Blue Ridge 
Mountains which are only 27 miles northwest, 
across the valley of the Dan River. 

Pilot Mountain is called an inselberg be- 
cause it is a prominent peak protruding from the 
nearly flat Piedmont plateau. 



TRAILS 

The paved road to the top of Pilot Mountain 
crosses the geologic contact between two distinct 
rock types. This contact is between light gray to 
tan, bedded quartzite overlying an interlayered 
sequence of gneiss and schist. The outcrop dis- 
plays the weathering characteristics of the rock 
types. The overlying, more resistant quartzite 
shows some rounded edges. The underlying 
gneisses and schists were scoured out through 



44 



chemical and mineral decomposition, removal of 
rock by surface water runoff, and by freezing and 
thawing. 

At the parking lot atop Pilot Mountain, the 
overlooks reveal panoramic views of rounded hills 
and broad valleys of the surrounding Piedmont 
plateau. The quartzite crest of Big Pinnacle (eleva- 
tion 2,421 feet) rises approximately 1,500 feet 
above the surrounding Piedmont. 

From the parkway area atop Pilot Mountain 
State Park, visitors can walk southeast toward 
Little Pinnacle. The little flat step-like surfaces are 
bedding planes that mark the tops of individual 
quartzite beds. Most of the quartzite beds are less 
than one inch thick. The "sparkles" in the quartzite 
are tiny flakes or crystals of the mica mineral 
muscovite. The mica is more evident on sunny 



days, because the flat surfaces of the mica reflect 
sunlight. The trace of the axis of the Sauratown 
Mountain anticlinorium passes through the gap 
between Little Pinnacle and Big Pinnacle. 

From Litde Pinnacle it is a pleasant walk 
south to the quartzite overlook; the southern view 
of the Piedmont plateau is spectacular. Also of 
interest are the spherical or curved weathering 
surfaces of the quartzite. The curved appearance 
forms as the fractures, joints, and horizontal bed- 
ding planes within the quartzite begin to weather in 
layers, forming rounded surfaces where angular 
surfaces once existed. This weathering process is 
known as spheroidal weathering. In places, cross- 
bedding is seen. Cross-bedding is particularly well 
exposed near the base of Big Pinnacle on the 
southwestern side. 




Big Pinnacle with the Sauratown Mountains and Hanging Rock in the background. 



45 



RAVEN ROCK STATE PARK 

Raven Rock State Park is located on the Cape 
Fear River in Harnett County, approximately 6 
miles northwest of Lillington. The park was estab- 
lished in 1970 in response to local efforts to protect 
the Raven Rock area from commercial develop- 
ment. The park now includes 2,752 acres along the 
Cape Fear River. 



GEOLOGY 

Raven Rock State Park lies near the fall line, 
a narrow zone marking the boundary between hard, 
resistant rocks of the Piedmont and softer rocks of 
the Coastal Plain. Rapids, such as Lanier Falls and 
Fish Traps, are common in the principal rivers 
along this zone. 

The Piedmont rocks at Raven Rock were de- 
posited as sediments in a shallow sea 500 million to 
800 million years ago. Layer upon layer of sand 
composed of the minerals quartz, feldspar, and 
mica fell to the sea floor and later formed rocks 




Historic 

Hillsborough Eno River 
State Park 




Weymouth Woods State Park 

i 

FAYETTEVILLE 



Raven Rock. 



called sandstone. The sandstone was then deeply 
buried and changed by heat and pressure 300 to 500 
million years ago and made into metamorphic 
rocks called gneiss and quartzite. Later, the meta- 
morphic rocks were gently arched upward, and 
exposed at the land surface through the processes 
of weathering and erosion. Millions of years ago 
the Cape Fear River, or an older river, deposited 
layers of gravel and sand on top of the metamorphic 
rocks. The gravel layers (terraces) are visible on 
the higher ridges in the park, particularly in the 
picnic area, where rounded, white quartz cobbles 
cover the ground. These gravels are mined nearby 
for construction and for decorative stone. The 
rocks in the park were exposed as the Cape Fear 
River continued to cut down through the gravels 
and metamorphic rocks. 

The most prominent geologic feature in the 
park is Raven Rock, named in 1854 for the ravens 
roosting on the rock ledges. Raven Rock is an 
outcrop of gneiss rising approximately 100 feet 
above the river. It was once a choice camp site for 
Indians. Raven Rock and other rock outcrops on 
the south side of the Cape Fear River were carved 
by the erosional forces of the river. The hardness 
of the gneiss and its resistance to erosion helped 
create these impressive exposures. In places, river 
banks are steeper on the south side of the river 
because of prevailing wind systems, meander 
development, rock structural controls, and the 



46 



Coriolis force. The Coriolis force is a principle 
that states that, as the Earth rotates, streams in the 
northern hemisphere are deflected to the right, 
looking downstream. 

A closer examination of Raven Rock reveals 
some interesting geologic features. Notice the 
lighter and darker colored layers in the rock. These 
layers represent changes in the composition of the 
original sediments when they were deposited in the 
sea. In places, quartz veins squeezed between the 
layers of gneiss. The veins originated as hot silica- 
rich liquids, that cooled and hardened into clear or 
cloudy quartz. A white mineral, feldspar, and 
shiny flakes of mica are also present. Some of the 
quartz veins are parallel (concordant) to the layers 
in the gneiss. Other veins cut across (discordant) 
the layers in the gneiss. 

Small amounts of a soft white mineral, called 
calcite, also occur in Raven Rock. This mineral has 
the chemical composition calcium carbonate. 
Geologists frequendy use a dilute acid test to iden- 
tify it. When dilute hydrochloric acid is placed on 
the mineral, it bubbles {effervesces) as C0 2 gas 
escapes. This is similar to the bubbling effect when 
vinegar is placed on baking soda. 

In places the rock looks blocky, and has one 
or more surfaces that are flat and straight, giving 
the appearance of having been cut by a saw. These 
are joint surfaces or cracks in the rock which 
formed as the overlying rock was removed by wind 
and water (erosion) or when the rock was folded. 
Usually it is possible to see numerous parallel 
joints and then other joints at different angles. 

The large pile of rocks at the base of Raven 
Rock represents fragments of rock that have bro- 
ken off and fallen. Some of the rocks near the river 
contain holes drilled many years ago when the rock 
was quarried. These holes were drilled into the 
rock by machines. Then dynamite was placed in the 
holes and exploded to break apart the large boul- 
ders. Fortunately, the quarrying ceased before 
Raven Rock was destroyed. 



TRAILS 

Campbell Creek Loop Trail follows the west 
bank of Campbell Creek where gneiss similar to 
Raven Rock is well exposed. The trail begins near 
the parking area, a relatively flat, upland area 
underlain by white, rounded river gravel. This 
gravel is mostly rounded quartz cobbles deposited 
by the ancestral Cape Fear River millions of years 
ago. The cobbles were probably carried from the 
higher Piedmont region and were gradually 
rounded as they moved along the river bottom 
during their long journey. Some of the cobbles 
have a reddish color that is iron stain. As the trail 
descends and approaches the creek, it winds 
through metamorphic rocks. Fragments of gneiss 
along the trail give a hint of the rock beneath the 
surface of the ground. Fragments of quartz on the 
ground surface mean that quartz veins are nearby. 
Quartz veins are sheet-like bodies which are used 
by geologists to locate water wells. They act as 
traps and channels for water to move beneath the 
land surface. If a well is drilled to intersect a quartz 
vein, the well commonly provides good supplies of 
water. 

The creek winds through gneiss and large 
rock exposures are visible in many places. The 
largest rock, or outcrop, is on the right bank where 
the creek takes a sharp left turn. Gravel bars occur 
in the creek where the creek changes direction or at 
other places where the water flow slows, causing 
larger, heavier particles of sand and gravel to drop 
from the water. 

Lanier Falls Trail branches from the 
Campbell Creek trail and follows the slope down to 
the Cape Fear River. Lanier Falls is a long outcrop 
of gneiss extending almost across the width of the 
river. 

Fish Traps Trail leads to another long out- 
crop of gneiss that extends almost across the width 
of the river. Years ago, Indians placed baskets 
below the rocks and trapped fish as they swam 
upstream. 



47 



SOUTH MOUNTAINS STATE PARK 

South Mountains State Park is in the western 
Piedmont physiographic province, 18 miles south 
of Morganton and 30 miles north of Shelby. The 
park is in the South Mountain range, a northeast- 
trending spur of the Blue Ridge Mountains. Eleva- 
tions in the park range from a high of 2,890 feet on 
Benn's Knob to a low of 1,250 feet along Jacob's 
Fork River. 

The park is characterized by mountain 
streams and ridges that provide good exposures of 
the rocks. The most outstanding feature in the park 
is High Shoals waterfall, which drops 70 feet over 
bare rock to the stream below. This high Piedmont 
area forms the headwaters of Jacob's Fork River. 



GEOLOGY 

The park lies within the Inner Piedmont 
geologic province. Rocks in this area were origi- 
nally formed nearly one billion years ago when 
sediments and volcanic rocks were washed into a 
sea or basin. These rocks were then deeply buried 
and intruded by hot, molten magma which later 
cooled to form igneous rocks, such as granite. The 
sedimentary, volcanic, and igneous rocks were 
then altered by heat and pressure (metamorphism) 
to form metamorphic rocks. Inner Piedmont rocks 
are primarily gneiss, schist, amphibolite, and in- 
trusive rocks of ultramafic to felsic composition. 
Metamorphosed granite exposed in the park is 
named Toluca Granite. Most of the gneisses and 
schists were contorted and folded by forces deep 
within the earth which built the Appalachian 
Mountains. The forces of erosion carved the land- 
scape we see today, slowly weathering the rocks, 
carrying sediment downstream, and leaving boul- 
der-laden valleys behind. The main rocks in the 
park are muscovite and biotite gneiss and schist, 
sillimanite schist, and granite gneiss {Toluca 
Granite). 

Outside the park in Burke, McDowell, and 




Rutherford Counties, gold was mined from about 
1828 until the mid 1900's. Much of the mining was 
from stream placer deposits along Brindle, South 
Muddy, North Muddy, and Silver Creeks and 
along the First and Second Broad Rivers. A few 
vein deposits were also worked. Gold is not mined 
from this area today and does not occur in the park. 

Monazite, a mineral that contains rare-earth 
elements, also occurs in streams outside the park. It 
was mined in the late 1800's, but there has been no 
production since 1910. 

Three diamonds were found in stream grav- 
els near Dysartsville, McDowell County, and two 
were found in Rutherford County. Diamonds are 
usually associated with rocks called kimberlites 
and lamproites, but these rocks have never been 
found in this area. The primary source of the 
diamonds has never been discovered. 



FALLS TRAIL 

Falls Trail leads up Jacob's Fork River to 
High Shoals Falls. In the lower part of the valley, 
the rock is well layered and contains many layers of 
schist. Farther up the valley, the rock is more 
massive and contains more quartz and less mica. 
Many interesting geologic features are on the trail 
after it crosses Shinny Creek. To the right of the 



48 



Pegmatite 




Feldspar crystals 



Pegmatite dike in gneiss. Since the pegmatite contains 
large amounts of coarse quartz and feldspar, it is more re- 
sistant to weathering than the gneiss and stands up in 
relief. This weathering process is differential weathering. 

trail, a large block of granite gneiss (Toluca Gran- 
ite) has broken and fallen. The block broke along 
a straight, flat surface called a joint plane. Joints 
are fractures that formed millions of years ago 
when the rocks were deformed or when stress was 
released as overlying rocks were eroded away. 
Layers of different minerals are exposed where the 
rock broke and reveal a coarse, white rock called 
pegmatite. The pegmatite formed during the last 
stages of igneous activity. It squeezed into the rock 
parallel to the layers in the granite gneiss. 

Farther along the trail, closely spaced joints 
in the Toluca Granite make the rock look as if it had 
been cut by the park rangers to form steps. These 
blocks formed by natural processes and fell from 
the sides of the valley. A large debris slide along 
the right side of the trail shows how these large 
blocks can move with great force down the valley. 
Many of the large boulders in the creek probably 
got there in this manner. 

Narrow, straight lines cross the surfaces of 
the large boulders in the creek. These lines are tiny 



fractures that were filled with a weather-resistant 
mineral such as quartz. Since the quartz is harder 
than the surrounding rock, it forms a thin, straight, 
raised ridge on the rock surface. 

Near the falls, a small cave formed where a 
slab of rock broke along a joint surface and rested 
at an angle against the side of the hill. There are not 
many solution caves, such as Linville Caverns, in 
North Carolina, but many caves develop from rock 
movements such as can be seen here. 

The climb up the valley is rewarded by a 
spectacular view of High Shoals Falls. Jacob's 
Fork River plunges 70 feet down the steep face of 
Toluca Granite. This surface is also a joint surface. 
Some of the large boulders below the falls may 
have broken from the face of the granite. The ap- 
pearance of the falls changes according to the 
amount of rainfall in the valley above the falls. 

Gneiss and schist crop out along less fre- 
quently used trails such as Shinny Trail, Possum 
Trail, Sawtooth Trail, and Jacob's Branch Trail. 
As in all state parks, rock collecting is not allowed. 




High Shoals Falls. 



49 



WILLIAM B. UMSTEAD 
STATE PARK 

William B. Umstead State Park is approxi- 
mately 5 miles west of Raleigh in the eastern 
Piedmont physiographic province. The park is the 
most urban park in the State, with rapid encroach- 
ment from Raleigh and Durham. Elevations in the 
park reach approximately 400 feet, with maximum 
relief of less than 1 50 feet. The park is divided into 
two sections: the Crabtree Creek section and the 
Reedy Creek section. 



GENERAL GEOLOGY 

Rocks within the park include igneous, 
metamorphic, and sedimentary types. The eastern 
two- thirds of the park is underlain by metamorphic 
rocks and igneous intrusive rocks that are between 
the Raleigh belt and the Carolina slate belt. The 
western one-third of the park is underlain by 
slightly metamorphosed volcanic and sedimentary 
rocks of the Carolina slate belt. Near the western 
park boundary, unmetamorphosed sedimentary 
rocks of the Durham Triassic basin are exposed. 

Raleigh belt rocks were originally depos- 
ited as sediments ata continental margin, probably 
during late Proterozoic or early Cambrian time. 
Rocks in the eastern portion of the park are 
primarily mica schist and mica gneiss intermixed 
with hornblende gneiss and ultramafic rock. 
They probably were originally deposited as 
mudstone, impure sandstone, and dark-colored 
intrusive rocks. Volcanic and sedimentary rocks 
of the Carolina slate belt lie west of these rocks. 
All of the original sedimentary and volcanic rocks 
were altered by heat and pressure (metamorphism) 
and folded to form the gneiss and schist we see 
today. 

About 200 million years ago during Trias- 
sic time, forces within the earth caused rocks to pull 
apart along the east coast of North America. Large 
areas of rock dropped down relative to rocks beside 
them and created long, narrow basins. These 



Welcome Center 
Kerr Reservoir State Recreation Area . 



Historic 

Hillsborough En° River 




basins were then filled with sediment as rivers 
rushed over the side of the basins and then slowly 
meandered through the center of the basin. Up to 
7,000 feet or more of sediment was deposited in 
some areas. The basins were much like the rift 
valleys in Africa today. Rocks from the Durham 
Triassic basin formed in this manner and are poorly 
exposed along the Western park boundary. The 
Jonesboro fault forms the boundary between the 
Triassic rocks and igneous and metamorphic rocks 
in the park. Fossil evidence indicates that dino- 
saurs roamed some of the area during Triassic time. 
Vertebrate fossils found in black shale include fish, 
amphibians, reptiles, and mammal-like reptiles. 



TRAILS 

Umstead Park has 17 miles of trails that 
follow the streams and cross hills forested with 
pines, hickory, and oak. Rocks are exposed best 
along the streams where erosion has left the more 
weather resistant rocks behind. 

Good exposures of intrusive rock, called 
granite, are at the Company Mill site on Crabtree 
Creek. Granite is a hard massive rock broken by 
many smooth, flat surfaces called joints. The 
rocks were not cut by man but formed these cracks 



50 



naturally. Because the joints enable the rock to be 
stacked closely, granite makes a good dam. An 
outcrop of granite is on the north side of Crabtree 
Creek. It is a good, solid foundation for the dam. 
Joints are also visible in the outcrop. 

Behind the dam, Crabtree Creek has cut 
down approximately 15 feet through sediment. 
When the mill was in operation, sediment carried 
by the creek slowly filled the bottom of the small 
lake. When the dam was broken, the creek cut 
down through the sediment to its original level. 

Biotite gneiss is exposed alongBeech Trail 
between Crabtree Creek and Sycamore Creek. 
Large boulders of gneiss form the steep valley of 
Sycamore Creek alongDogwoodTrail. The gneiss 
is composed of biotite mica, quartz, and feldspar in 
alternating dark and light layers. 



quartzite. This shows that the stringers formed 
later than both of the rock units. A few fragments 
of quartzite are in the gneiss, which indicates that 
the sediments that formed the gneiss were depos- 
ited after the sediments which formed the quartzite. 
Quartzite is also well exposed in the small quarry 
farther south on Sycamore Trail. Quartzite, as the 
name implies, is composed mostly of quartz with 
minor feldspar and mica. It may have been origi- 
nally deposited as a beach sand. Stone was mined 
from the quarry during the 1930' s for use in the 
construction of walls, bridges, and buildings in the 
park. 

A quartz-rich gneiss is exposed along the 
small creek east of the main picnic area. The gneiss 
contains only a small amount of biotite mica and is 
much lighter in color than the gneiss along Beech 
Trail and Dogwood Trail. 



The spillway below Highrock Lake Dam 
on Sycamore Creek can be reached from the Syca- 
more Trail. This outcrop shows excellent expo- 
sures of gneiss in contact with quartzite. Small 
stringers of quartz crosscut both the gneiss and 



Metamorphosed volcanic rocks and Trias- 
sic sedimentary rocks are not well exposed in the 
park. They are poorly exposed along Sycamore 
Creek near the western edge of the park. No trails 
lead to this area. 



1 Wary King Mountain lault 


13 Brevard lault z 




25. Silver Hill fault 


2 Hayesville lauN 


14. Bowens Creek 


laull 


25. Silver Valley shear zo 




15. Ridgewaylaul 




27. Denton anticline 


4 Fork Ridge faufl 


16. Stone Ridge la 




28. New London syncline 


5. Brushy Mounlainlauh 


17 Unnamed taut 




29. Troy anticline 


5. Mine Ridge fault 


18. Dan River faufl 




30. Colon cross -structure 


7 Sione Mountain Ihrusl 


19. Newton amilof 




31. Jonesboro lault 


3 Table Roc* thrua 


20 Eutola lault 




32 Raleigh anticline 


3 Lirmlle Falls fault 


21 Kings Mountai 




33. Nulbush Creek mylon 


Unnamed fault 


22 Soulh Fork an 




34. Wake-Warren anticline 


1 Unnamed faufl 


23 Boogertown sh 


ear zone 


35 Spring Hope synform 


2. Unnamed fault 


24 Gold Hill faufl 




36 Cape Fear arch 




Pre-metamorphic ihrusl fouli 
Posl metamorphtc thrust laul 



— Syncline 

-ft Overturned anticli 

— * Direction of plunge 



Schist 
i Volcanic Rock 

-3000 — Contour on pre-Mesozoic basement rock 



GEOLOGIC BELTS AND MAJOR STRUCTURES IN NORTH CAROLINA 



51 



MOUNT JEFFERSON STATE PARK 

Mount Jefferson State Park is in southeast- 
ern Ashe County. The park, established in 1956, 
includes 541 acres of forest trees, shrubs and wild- 
flowers that make it a naturalist's paradise. 



GEOLOGY 

Mount Jefferson State Park is located in the 
southern Blue Ridge Highlands at its northeastern 
boundary with the New River Plateau. Mount 
Jefferson is an isolated northwest-trending moun- 
tain that reaches a maximum elevation of 4,684 
feet. It rises at least 1 ,600 feet above the level of the 
nearby stream valleys. 

Amphibolite and gneiss of the Ashe Meta- 
morphic Suite underlie most of Mount Jefferson. 
These rocks were originally deposited 600 to 800 
million years ago in a trough or basin in the floor 
of an ancient sea. Some material was washed into 
the basin from the surrounding land areas, but other 
material was deposited as volcanic debris from 
now extinct volcanoes. The black rock, amphi- 
bolite, seen in the park today is an example of 
volcanic rocks that have been changed by heat and 
pressure, metamorphism, to form metamorphic 
rock. 

The reason Mount Jefferson is so high is 
difficult to explain. Amphibolite is normally not 
very resistant to erosion and is usually found in 
lower elevations. The gneisses and schists, which 
are in the valley here, normally have a higher 
quartz content and are more resistant to erosion. It 
has been suggested that the gneisses and schists in 
this area are thinner than normal, making them me- 
chanically weaker and so eroding more easily. The 
topography is also controlled by joint mdfracture 
patterns in the area. 



VISTAS AND TRAILS 



The first overlook past the park office on 



BANNER 
ELK 




Roan ■ 
Mountain Gran 
M< 



South Mountains 
State Park 



State Road 1152 (leading to the Forest Service 
tower) presents an excellent panoramic view of the 
northern part of the Southern Blue Ridge High- 
lands. To the south and in the far distance, the lofty 
Black Mountains appear to the west of the closer 
and jagged spine of Grandfather Mountain. The 
Black Mountains are the highest mountains in 
eastern North America with elevations of up to 
6,684 feet, on Mount Mitchell. Roan Mountain, 
with an elevation of 6,285 feet, is also visible in the 
distant southwest. To the near west is Bluff Moun- 
tain (5,100 feet) and Paddy Mountain (4,331 feet). 
Phoenix Mountain (4,710 feet) and Little Phoenix 
Mountain (3,873 feet) are to the north and are also 
underlain by amphibolite. White Top Mountain 
(5,344 feet) and Mount Rogers (5,729 feet) are 
visible to the distant northwest. 

The second overlook on State Road 1 152 
provides magnificent panoramic views also. This 
overlook is perched upon a very steep rock outcrop 
of amphibolite. The outcrop and nearby road cut 
are excellent places to examine closely the amphi- 
bolite of the Ashe Metamorphic Suite. The out- 
crop is steep and somewhat dangerous so visitors 
should be careful! The amphibolite is distinctly 
layered or foliated. Differential weathering, 
where some minerals are weathering faster than 
others, is visible. Resistant layers of the minerals 
epidote and quartz stand a few inches above the 
less resistant amphibole and feldspar layers. 



53 




Photomicrograph of muscovite-biotite schist. Geologists 
cut paper-thin slices of rock to study minerals with a pet- 
rographic microscope. This thin section shows a spiral- 
shaped garnet. During metamorphism, the garnet de- 
formed as it grew. Mica minerals, muscovite and biotite, 
are aligned parallel to each other and give the rock a 
foliation. This mineral alignment also occurred during 
metamorphism. 

Approximately 750 feet from the parking 
lot along the trail to the fire tower is the geological 



contact between amphibolite and a layer of gneiss. 
The gneiss layer is 700 to 1,000 feet thick and is 
more resistant to weathering than is the amphi- 
bolite. This gneiss underlies the fire tower and its 
resistance to erosion may be the main reason the 
peak is higher than the remainder of the ridge. 

The Rhododendron Trail, a one-hour self- 
guided nature trail, travels the ridge line to 
Luther's Rock. From Luther's Rock there is a 
spectacular view to the north and east of the New 
River Plateau, the South Fork of the New River, the 
crest of the Blue Ridge Escarpment, and the Blue 
Ridge Parkway. Except for the first and last few 
stations, the trail is in amphibolite of the Ashe 
Metamorphic Suite. Stations 9, 10, and 1 1 are bare 
rock exposures of amphibolite and are known col- 
lectively as Luther's Rock. These black-colored 
rocks were once ancient lava flows or volcanic 
rocks that have been changed by heat and pressure 
{metamorphism). They have also been folded by 
the forces that produced the Appalachian Moun- 
tains. These rocks, rich in iron and magnesium, 
influence the type of vegetation that grows in the 
soil here. 




Mount Jefferson. 



54 



MOUNT MITCHELL STATE PARK 

Mount Mitchell State Park is about 20 
miles northeast of Asheville. The entrance to the 
park is at milepost 355.4 of the Blue Ridge Park- 
way. Established in 1915 as the State's first park, 
it now includes 1,469 acres in the Black Mountain 
range. Mount Mitchell, elevation 6,684 feet, is the 
highest peak in the eastern United States. 

Mount Mitchell was named for Dr. Elisha 
Mitchell, a geologist, minister, and professor, 
probably the first man to measure the peak, prior to 
1 844. He determined that the peak was higher than 
Mount Washington, in New Hampshire, then con- 
sidered the highest peak in eastern America. Dr. 
Mitchell made a second trip to the mountain in 
1857 to make additional measurements but fell to 
his death. N.C. Senator Thomas Clingman also 
claimed to be the first to measure the peak and this 
controversy has never been settled. Dr. Mitchell's 
grave lies near the summit of the mountain. 

A visit to the summit of Mount Mitchell is 
rewarded with magnificent vistas in all directions. 
Looking east, the Blue Ridge front falls quickly 
into the deeply dissected Piedmont Plateau. The 
Blue Ridge front is a steep scarp which may have 
been formed by erosion. It may also simply repre- 
sent the difference in base level between higher 
rivers in the Blue Ridge and the lower rivers in the 
Piedmont. 

The Catawba River basin is visible in the 
foreground to the east. The Catawba River and the 
Linville River unite to form Lake James. The 
Catawba flows east- southeast from Lake James 
approximately 150 miles where it joins the Wa- 
teree River and becomes part of the Santee River 
basin in South Carolina. 

On clear days it is possible to see beyond 
Lake James 80 to 90 miles to the eastern horizon. 
To the northeast is Grandfather Mountain and the 
majestic peaks of Table Rock andHawksbill along 
the east side of the Linville Gorge. A mine in the 
Spruce Pine Mining District stands out as a white 



Roan 
Mountain 




South Mountains 
State Park 



patch to the northeast. This mining district is 
famous for its large alaskite deposits which yield 
feldspar and mica, minerals for which North Caro- 
lina annually leads the nation in production. 
Alaskite is white igneous rock, similar to granite, 
that is composed mostly of quartz, feldspar, and 
mica. The area is also noted for its gemstones, most 
notably emerald and aquamarine. 

Mount Craig, named for Governor Locke 
Craig who was important in preserving the moun- 
tain as a state park, is the peak north of the parking 
area. To the west are the headwaters of the Cane 
River, Cane River Gap, Big Butt, and Ogle 
Meadow. Farther to the west, the Appalachian 
Mountains stretch out toward the Great Smoky 
Mountains. The peak to the south with two radio 
antennae on its summit is Clingman's Peak. South 
of Clingman's Peak, the Black Mountains give way 
to the Great Craggy Mountains. 



GEOLOGY 

Rocks underlying Mt. Mitchell are in- 
cluded in the Ashe Metamorphic Suite of rocks. 
These rocks were deposited approximately 600 to 
800 million years ago, during Precambrian time, 
in an ancient sea. Sand, clay and rock fragments 
were washed into the sea from the surrounding land 
area and were mixed with material ejected from 



55 



nearby volcanoes. Approximately 500 million 
years ago, as the landmasses moved together, the 
sea closed, thrusting some rocks westward over 
other rocks, and beginning the formation of a 
mountain chain. The rocks were deeply buried and 
then, about 430 to 480 million years ago in 
Ordovician time, were altered by intense heat and 
pressure to form metamorphic rocks called gneiss 
and schist. This process is called metamorphism. 
Additional sediments were deposited at this time, 
and granitic rocks were intruded. Metamorphism 
again affected the rocks during the late Paleozoic. 
During middle to late Paleozoic, as a result of shift- 
ing continental plates, North America collided 
with another land mass, possibly Africa, and thrust 
the rocks westward to form the Appalachian 
Mountain chain. 

Most rocks exposed in the park are biotite 
gneiss or metagraywacke. They were originally 



deposited as impure sandstones but have been 
metamorphosed to their present composition and 
texture. Primary minerals, quartz, feldspar, and bi- 
otite mica, formed through metamorphism of the 
original sand and clay. The minerals are concen- 
trated into dark and light layers giving the rock a 
layered or gneissic appearance. The dark layers 
contain more biotite mica and the lighter layers 
contain more quartz and feldspar. 

The rugged mountain landscape is the re- 
sult of millions of years of gradual uplift, erosion, 
and slow deterioration of the rocks. The slow proc- 
esses of erosion gradually wore the rocks down 
into sand and clay and slowly washed them down 
rivers into the sea. The processes of erosion con- 
tinue today, slowly carrying away small particles 
of rock and further changing the shape of the 
mountain chain. 




Mount Mitchell. 



56 



NEW RIVER STATE PARK 

New River State Park is in northwestern 
North Carolina in Ashe and Alleghany Counties. 
The focus of the park is a 22-mile stretch of the 
South Fork of the New River and a 4.5-mile stretch 
of the New River beyond the junction of the North 
and South Forks of the river. This segment of the 
river is within both the State and Federal Scenic 
River systems. It is managed by the North Carolina 
Division of Parks and Recreation. 



GEOLOGY 

The park is in the New River Plateau of the 
Blue Ridge physiographic province. The plateau 
has relatively low relief, with the average relief 
approximately 600 feet. Major streams cross the 
plateau in sinuous courses and form exaggerated 
meanders that have long, straight reaches. Mean- 
ders are a series of regular curves or bends in the 
course of a river. The streams flow northwest at 
right angles to the trend of the bedrock. 

Rocks that underlie New River State Park 
belong to two major geologic units found in the 
western part of the State. The oldest unit is biotite 
granitic gneiss of the Elk Park Plutonic Group. It 
represents some of the most ancient rocks found in 
the Appalachians, over one billion years old. The 
second major rock unit includes gneiss and schist 
of the Ashe Metamorphic Suite. 

The biotite granitic gneiss originally 
formed as large granite bodies that solidified from 
hot, molten magma in the cores of ancient moun- 
tains. The ancient mountains eroded away long 
ago. A small portion of the biotite granitic gneiss 
probably formed from sediments that were depos- 
ited in a basin or sea. The igneous and sedimentary 
rocks have been changed in appearance by tem- 
perature and pressure, a process called metamor- 
phism. 

The gneisses and schists of the Ashe Meta- 
morphic Suite formed where sediment washed 



New River 



BANNER 
ELK 




Roan ■ 
Mountain Gran 
Mi 



South Mountains 
State Park 



into a sea. At the same time, volcanoes were active 
nearby, and volcanic debris also washed into the 
sea. This layered sequence of material was then 
buried, metamorphosed, deformed, and then ex- 
posed at the Earth's surface through uplift and 
erosion. Dark-colored, iron- and magnesium-rich 
rocks called ultramafic rocks are also interlayered 
with the gneiss. 

The South Fork of the New River flows 
across an area where, during the formation of the 
Appalachian Mountains, the rocks were gently 
arched downward. This downfold in the rocks is 
called the Ararat River Synclinorium. The large 
fold controls the outcrop pattern of rocks along the 
South Fork of the New River. 



GEOLOGIC FEATURES 

Many geologic features and processes can 
be observed along the New River. These include: 
rapids, potholes, floodplains, meanders, erosion, 
transportation, and deposition. 

Rapids along the river are the result of 
differential erosion, where softer, weaker rocks 
are rapidly worn away and harder, more resistant 
rocks remain to form rapids or waterfalls. Along 



57 



the New River, quartz-rich gneisses are usually the 
most resistant layers and form many of the rapids. 

The tight meandering nature of the New 
River is unusual for a stream with such a moderate 
gradient or flow. It can be attributed to a time in the 
geologic past when the South Fork was flowing 
much more gently. The area was then uplifted and 
tilted, causing the river to cut deeper into the rocks. 
Meanders result from the flow of water through a 
channel. They are the form by which, in making 
a turn, a river experiences the least flow resistance, 
does the least work, and releases energy the most 
uniformly along its course. Meanders change po- 
sition almost continually. 

The New River valley provides an excel- 
lent opportunity to study stream channel develop- 
ment. The river cuts steep slopes on the outsides of 
bends where the velocity of the water flow is the 
greatest. Deposition occurs on the insides of bends 
where the stream velocity is the least. Potholes, 
circular, elliptical holes in the rocks, often develop 




The meandering course of the New River. 



where bedrock is exposed in the bed of the river. 
They begin as shallow depressions where swirling, 
turbulent water drives sand, pebbles and even 
cobbles round and round the depression. This 
continued abrasion wears the potholes even 
deeper, as if the bedrock is being bored by a giant 
drill. 



ACCESS AREAS 

The Wagoner Road access area (Site #1) is 
on a narrow floodplain opposite the largest sand 
bar (island) within the channel of the river. This 
island formed as the flow of the river slowed and 
could no longer carry the heavier particles. The 
larger sand and gravel particles then dropped to the 
river bottom. Downstream at the northern end of 
the canoe access and camping area, a resistant 
layer of gneiss is exposed. 

Site #3 is for river travelers and has no road 
access. The site is on the northwest side of a large 
meander. It is on the inside or depositional side of 
the meander. On the opposite side of the river, the 
valley wall is much steeper and, in places, is a rock 
cliff. The cliff is composed of amphibolite, a dark 
rock containing hornblende and plagioclase feld- 
spar, and gneiss of the Ashe Metamorphic Suite. 

Site #5 is a primitive camping area across 
the river from an area known locally as the bluffs. 
The bluffs is a granite wall that rises 200 feet above 
the river level. The granite is approximately 1 . 1 
billion years old. The camp site is on the inside or 
depositional side of the river, but the bluffs are on 
the outside or cut bank where the river flow is 
greater. On the northeast side of the picnic area is 
a large sand bar that formed where the river flow 
began to slow. The river could no longer transport 
the larger particles and they fell to the river bottom, 
gradually building the bar. 



58 



STONE MOUNTAIN STATE PARK 

Located in Wilkes and southeastern Al- 
leghany counties, the park is approximately 17 
miles northwest of North Wilkesboro and 9 miles 
southeast of Sparta. Established in 1968 with about 
2,100 acres, it now contains about 1 1,000 acres. 

Stone Mountain State Park is dominated by 
a granitic dome which can be seen for many miles 
when approaching the park. The steep sides of the 
granite mass attract rock climbers from many ar- 
eas. The many miles of park trails take the visitor 
past swiftly cascading waterfalls rushing over 
granite ledges into cool deep pools. The streams 
spread out across smooth, slippery water-polished 
surfaces ideal for water sliding. Hawks and birds 
of prey rise on thermals, rising currents of warm 
air, where the exposed granitic rock is heated by 
the sun. Beauty Falls (also known as Stone 
Mountain Falls or Little Falls) is formed where Big 
Sandy Creek plunges over a granitic face over 200 
feet high. 

The granitic mountain dominating the 
park's skyline has an elevation of 2,305 feet. It 
rises almost 700 feet above the valley floor. 




BANNER 
ELK 




Roan ■ 
Mountain Gran 
Mi 



South Mountains 
State Park 



GEOLOGY 

There are two main rock units in this park. 
Biotite gneiss, the oldest rock unit in the park, 
formed from muddy and sandy sediments, and 
from volcanic lava flows and ash that were depos- 
ited between 500 to 600 million years ago. These 
sediments were buried and compressed to form 
rocks; eventually, they were exposed at the land 
surface by the processes that make mountains. 
Geologists refer to these rocks as the Alligator 
Back Formation. 

Stone Mountain, Wolf Mountain, and the 

other high areas of the park are composed of a 
second rock unit, similar to granite. This rock unit 
is about 390 million years old. The granite formed 
from magma, molten rock, several miles deep in 
the earth. Eventually, the magma cooled and crys- 
tallized, and formed the granitic body. 

About 200 million years ago, erosion be- 
gan stripping away some of the overlying rocks. 
As the miles of rock overlying the granitic rock 
were removed by erosion, the release in pressure 
caused the rock mass to expand upward. As it 
expanded upward, lines of fractures developed 
parallel to the present ground surface, and slabs of 
rock, exfoliation sheets, developed. These curved 



Stone Mountain, an exfoliation dome. 



59 



exfoliation sheets help control the mountain's 
dome shape. Stone Mountain is an exfoliation 
dome. 

Once uncovered, granitic rocks are more 
resistant to erosion than the metamorphic rocks 
which they intruded. Thus, Stone Mountain Creek 
flows along the curved shape of Stone Mountain at 
its north end until it turns and cuts through the 
granite along a plane or surface of weakness in the 
granitic rock. 

Wolfe Rock, Cedar Rock, Little Stone 
Mountain, Buzzard Rock, First Flat Rock, and 
Hitching Rock are bare rock exposures that give 
this park its distinctive appearance. Birds of prey 
are commonly seen riding the thermals from the 
heating of these bare granite surfaces. 

Indian Den Rock and Rock House are 

natural rock shelters formed from fallen granite 
boulders that touch. The open spaces formed under 
these boulders are large enough to provide the park 
visitor with shelter from a sudden rain shower. 

Along the park's trails, smaller features of 
geologic interest can be seen; these include weath- 
ering pits, joints, and xenoliths. 

Weathering pits are irregularly rounded 
depressions in the granitic rock. Chemical and 
physical processes are responsible for their forma- 
tion. Weathering pits begin to form when some 
minerals weather more rapidly than others. Water 
collects in the resulting spaces in the rock surface; 
water continues to collect in these depressions and 
they slowly enlarge, merging with others, to form 
the distinctive "pock-marked" surface. The plant 
communities and soils that eventually developed 
on the granite began when lichens and moss colo- 
nies established a "toe hold" in these weathering 
pits. These plants provided organic acids which 
helped to decompose the minerals and produce a 
thin soil horizon. Eventually, grasses and flowers 
flourished, and finally, soils became sufficiently 
thick to support pine and hardwood communities. 



Joints are fractures in the rock along which 
there has been no movement. S everal different ori- 
entations of joints are present in the granitic rocks 
at Stone Mountain State Park. Some joints devel- 
oped during exfoliation parallel to the topography 
of the mountains. The curved granitic slabs lying 
loosely on top of the rock pavements at Stone 
Mountain are the result of sheet joints. Sheet joints 
develop parallel to the ground's surface as overly- 
ing rocks are removed and the granite expands. 
Other more steeply inclined joints occur within the 
granite mass and are the cracks used by climbers to 
ascend Stone Mountain. Joints and intersecting 
joints create the spectacular Great Arch and other 
climbing routes such as the Great White Way, 
Mercury's Lead, and others. 

Xenoliths are the remains of older meta- 
morphic rocks which were invaded by the molten 
granitic material. Where the hot, molten material 
did not dissolve all of the blocks of the surrounding 
rock, xenoliths formed. The xenoliths are com- 
posed of biotite gneiss and amphibolite; they ap- 
pear as the dark clots in the granite. 




A weathering pit in granite. 



60 



OTHER STATE PARKS 

Boone's Cave State Park is in the Pied- 
mont physiographic province approximately 14 
miles west of Lexington. It is the legendary site of 
Daniel Boone's hide-out on the east side of the 
Yadkin River. The cave extends for about 80 feet 
into granitic rock, referred to as the Churchland 
Pluton. This granite formed 280 million years ago 
and is interesting because of the large feldspar 
crystals it contains. The crystals, in places 2 to 3 
inches across, weather out on the surface of the 
ground. When an igneous rock contains large 
crystals surrounded by smaller crystals, it is called 
a. porphyry or, in this instance, aporphyritic gran- 
ite. This type of texture gives geologists clues 
about how the rock formed. 

Goose Creek State Park is in Beaufort 
County on the north bank of the Pamlico River 
between Washington and B ath . It is in the flat, low- 
lying tidewater region of the Coastal Plain. In this 
portion of the Pamlico River, fresh water from the 
river is mixed with salt water from the Pamlico 
Sound to form brackish water, typical of Coastal 
Plain estuaries. The park is underlain by surface 
sand and clay which covers the older Coastal Plain 



formations. The park is a good place to observe 
marsh and swamp environments. 

The 1987 General Assembly appropriated 
funds to establish Lake James State Park. The site 
is 1 3 miles west of Morganton on the south shore of 
Lake James, built in 1919 by Duke Power Com- 
pany. The park lies within the Inner Piedmont 
geologic province. Rock types are mostly musco- 
vite (white mica) schist and biotite (black mica) 
gneiss. Mica flakes in the soil reflect the large 
amount of mica in the rocks beneath the surface of 
the ground. 

Theodore Roosevelt Natural Area is 7 

miles west of Atlantic Beach on one of the state's 
barrier islands, Bogue Island. The natural area was 
donated to the state by the 26th President of the 
United States. It is located around the North 
Carolina Marine Resources Center, and represents 
brackish marsh and maritime forest environments. 
The main park trail crosses a forested ridge and 
swale topography. 

Waynesboro State Park is off US 117 
Bypass in Goldsboro. It is on the Neuse River and 
is set in a typical Coastal Plain river environment. 




61 



ACKNOWLEDGEMENTS 

The North Carolina Division of Parks and 
Recreation provided information and some of the 
photographs. Their comments and suggestions 
during early stages of this project were most help- 
ful. Suggestions from Mike Dunn and Tom How- 
ard were especially useful in preparing the text. 
The park superintendents and rangers were helpful 
in suggesting the most popular geologic features 
and trails. 

The geologic descriptions are a combined 
effort of the North Carolina Geological Survey 
staff geologists. Authors of the guides to individ- 
ual parks are listed in the Contents. The editor 
accepts responsibility for any errors which oc- 
cured during editing in an attempt to achieve uni- 
formity. The general geology (page 5) was modi- 
fied from the Guide to Geologic and Other Natu- 
ral Resources Points of Interest Along Interstate 
40 by Edward R. Burt, III. 

Review comments by Phyllis Danby, Divi- 
sion of Land Resources, Land Records Manage- 
ment Section, and Edward F. Stoddard, North 
Carolina State University, Department of Marine, 



Earth, and Atmospheric Sciences were especially 
helpful. 

Photographs were provided by the follow- 
ing: Edward F. Stoddard (page 28 and 54); N.C. 
Division of Parks and Recreation (pages 20, 49, 56, 
58, and 60); N.C. Travel and Tourism Division 
(pages 16, 33, and 45); N.C. Wildlife Resources 
Commission (Ken Taylor-pages 7, 12, 22, 59, and 
61; Curtis Wooten-page 26); N. C. Department of 
NRCD, Division of Public Affairs (Jim Page- 
pages 32, 39, and 52); N. C. Geological Survey (P. 
Albert Carpenter, Ill-front cover and pages 40, 
and 46; Patricia E. Gallagher-pages 8 and 17; Char- 
les W. Hoffman-page 18; Carl E. Merschat-page 
54); N. C. Geological Survey Bulletin 89 (page 
25); N. C. Geological Survey Bulletin 8 (page 43); 
U.S. Army Corps of Engineers (page 15); U.S. 
Geological Survey (page 37). The drawing on page 
30 was modified by William F. Wilson from a 
drawing in U.S. Geological Survey Bulletin 1595. 

Location maps were modified from maps 
provided by the N. C. Travel and Tourism Divi- 
sion. Denise Smith, artist-illustrator, Department 
of NRCD, Division of Public Affairs, designed the 
front cover and pages 7, 26, and 52. 




62 



GLOSSARY* 

A 

absolute age - The age in years, commonly based on radio- 
metric dating techniques. 

Alligator Back Formation - A mappable unit of rocks 
consisting primarily of gneiss, schist, amphibolite, and minor 
amounts of quartzite and marble which are exposed along the 
Blue Ridge escarpment from Wilkes County, N.C., to Patrick 
County, Virginia. 

artesian - An adjective referring to ground water confined 
under hydrostatic pressure. 

amphibolite - A metamorphic rock consisting mainly of 
amphibole and plagioclase feldspar with little or no quartz. 

anticlinorium - A composite anticlinal structure of regional 
extent composed of lesser folds. 

argillite - A compact rock, derived either from mudstone or 
shale, that has undergone a somewhat higher degree of 
induration than mudstone or shale but is less clearly lami- 
nated than shale and without its fissility, and that lacks the 
distnctive cleavage of slate. 

Ashe Metamorphic Suite - Fine-grained, thinly layered 
sulfur-rich, biotite-muscovite gneiss, interlayered with vary- 
ing amounts of mica schist and amphibolite in central Ashe 
County. 



B 



barrier island - A long, narrow coastal sandy island, repre- 
senting a broadened barrier beach that is above high tide and 
parallel to the shore, and that commonly has dunes, vegetated 
zones, and swampy terranes extending lagoonward from the 
beach. 

basalt - A general term for dark-colored mafic igneous rocks, 
commonly extrusive but locally intrusive, composed chiefly 
of calcic plagioclase and clinopyroxene; the fine grained 
equivalent of gabbro. 

basin - A low geographic area in which sediments may 
accumulate. 

Battleground Formation - A mappable unit of rocks in the 
Kings Mountain belt consisting primarily of sericite schist 
and also containing interlayered metavolcanic and metasedi- 
mentary rocks 



bedding - The arrangement of a sedimentary rock in beds or 
layers of varying thickness and character. 

bedding plane - A planar or nearly planar bedding surface 
that visibly separates each successive layer of stratified rock 
from the preceding or following layer. 

bedrock - A general term for the rock, usually solid, that 
underlies soil or other unconsolidated, superficial material. 

biotite - A black, dark brown, or dark-green iron- and 
magnesium-bearing mineral of the mica group. 

blowout - A general term for a small saucer-, cup-, or trough- 
shaped hollow or depression formed by wind erosion on a 
pre-existing dune or other sand deposit. 

bog - Waterlogged, spongy ground, consisting primarily of 
mosses, containing acidic, decaying vegetation that may de- 
velop into peat. 



calcite - Calcium carbonate in its hexagonal crystalline form. 

Cambrian - The oldest period of the Paleozoic Era, lasting 
from 570 to 500 million years ago. 

cape - An extensive, somewhat rounded irregularity of land 
jutting out from the coast into a large body of water. 

Cape Fear Arch - A subsurface northwest-southeast-trend- 
ing anticlinal structure composed of pre-Cretaceous rocks 
that plunge gendy to the southeast. The arch is buried beneath 
Coastal Plain sediments in parts of Bladen, Columbus, and 
Brunswick counties, N.C. 

cast - Secondary rock or mineral material that fills a natural 
mold. 

Cenozoic - The youngest and present geologic era, which 
started about 65 million years ago. 

clast - An individual constituent, grain, or fragment of a 
sediment or rock, produced by the mechanical weathering 
of a larger rock mass. 

Cleavage - The property or tendency of a rock to split along 
secondary, aligned fractures or other closely spaced, planar 
structures or textures, produced by deformation or metamor- 
phism. 

Coastal Plain - The generally flat land area between the 
ocean and the hills of the Piedmont, blanketed by Meso- 
zoic and Cenozoic sediments. 



* Definitions are modified, in part, from the Glossary of Geology, (1980) American Geological Institute. 

63 



concordant - A contact between an igneous intrusion and the 
country rock that parallels the foliation or bedding planes 
of the latter. 

conglomerate - A sedimentary rock consisting of rounded, 
waterworn fragments of rock or pebbles cemented together 
by another mineral substance. 

continental shelf - The gently sloping, shallowly submerged 
marginal zone of the continents extending from the shore to 
an abrupt increase in bottom inclination. 

coquina - A sedimentary rock composed almost entirely of 
cemented mollusk shells and other invertebrate fragments. 

Coriolis force - The tendency of particles in motion on the 
Earth's surface to be deflected to the right in the Northern 
Hemisphere and to the left in the Southern Hemisphere. 

creep - The slow, more or less continuous downslope move- 
ment of mineral, rock, and soil particles under g r a v i t a - 
tional stresses. 

Cretaceous - The third and youngest of the three Mesozoic 
periods, lasting from approximately 141 to 65 million 
years ago. 

cross-beds - Sedimentary layers inclined at an angle to the 
main planes of stratification. 

crystalline - A general term used to refer to igneous and 
metamorphic rocks. 



D 



deflation - The sorting out, lifting, and removal of loose, dry 
fine grained particles by the turbulent eddy action of the 
wind. A form of wind erosion. 

delta - The low, nearly flat, alluvial tract of land at or near the 
mouth of a river, commonly forming a triangular or fan- 
shaped plain of considerable area, crossed by many distribu- 
taries of the main river, perhaps extending beyond the general 
trend of the coast, and resulting from the accumulation of 
sediment supplied by the river in such quantities that it is not 
removed by the tides, waves, and currents. 

deltaic — Pertaining to a delta. 

Devonian - A period of the Paleozoic era, spanning the time 
between 400 and 345 million years ago. 

diabase - A fine-grained, black intrusive rock composed 
principally of labradorite feldspar and pyroxene. 



differential weathering - Weathering that occurs at different 
rates, as a result of variations in composition and resistance 
of arockor differences in intensity of weathering, and usually 
resulting in an uneven surface where more resistant material 
stands higher or protrudes above softer or less resistant parts. 

dike - A tabular igneous intrusion that cuts across the bedding 
or foliation of the surrounding rock. 

dinosaur - Any member of the extinct reptile orders Sauris- 
chia and Ornithischia. 

diorite - A plutonic rock intermediate in composition be- 
tween felsic and mafic, characteristically composed of dark- 
colored amphibole, sodium-rich plagioclase, pyroxene, and 
sometimes a small amount of quartz. 

discordant - A contact between and igneous intrusion and 
the surrounding rock that is not parallel to the bedding or 
foliation planes of the latter. 

dissected - The process of erosion by which a relatively even 
topographic surface is gradually sculptured or destroyed by 
the formation of gullies, ravines, canyons, or other kinds of 
valleys. 



E 



Eocene - The second oldest epoch of the Paleogene Period, 
lasting approximately from 55 to 37 million years ago. 

eolian - Pertaining to the wind. 

eon - The largest geologic time unit, consisting of eras and 
their subordinate time units. 

epidote - A yellowish-green, pistachio-green, or blackish- 
green mineral. 

epoch - A geologic time unit of intermediate rank between 
periods and ages. 

era - A geologic time unit of rank between eon and period. 

erosion - The general process or group of processes whereby 
the materials of the Earth's crust are loosened, dissolved or 
worn away, and simultaneously moved from one place to 
another, by natural agencies. 

escarpment - A long, more or less continuous cliff or 
relatively steep slope facing in one general direction, break- 
ing the continuity of the land by separating two level or gently 
sloping surfaces, and produced by erosion or by faulting. 

eustasy - The world wide sea-level regime and its fluctua- 



64 



tions caused by variations in the volume of the oceans, and 
variations in the quantity of sea water caused by continen- 
tal ice cap fluctuations. 

exfoliation - The process by which plates, or shells of rock, 
from less than a centimeter to several meters in thickness, are 
successively spalled or stripped from the bare surface of a 
large rock mass. 



G 



gabbro - A group of dark-colored, mafic intrusive igneous 
rocks composed principally of calcic plagioclase and clino- 
pyroxene, with or without olivine and orthopyroxene. It is the 
approximate intrusive equivalent of a basalt. 

geologic column - The sequence of rocks in a designated part 
of the Earth. 



facies - The aspect, appearance and characteristics of a rock 
unit, usually reflecting the conditions of its origin; the envi- 
ronment in which a rock was formed. 

fall line - An imaginary line or narrow zone connecting the 
waterfalls on several adjacent, near-parallel rivers, marking 
the points where these rivers make a sudden descent from an 
upland to a lowland, as at the edge of a plateau. 

fanglomerate - A sedimentary rock consisting of slightly 
water-worn, heterogeneous fragments of all sizes, deposited 
in an alluvial fan and later cemented into a firm rock. 

feldspar — Any of a group of abundant, rock-forming 
minerals occurring principally in igneous and metamor- 
phic rocks, and consisting of silicates of aluminum with 
potassium, sodium, calcium, and, rarely, barium. 

felsic - An adjective applied to an igneous rock having 
abundant light-colored minerals, most commonly feldspar 
and quartz. 

fissure - A surface of fracture or a crack in a rock along which 
there is a distinct separation. 

float - A general term for isolated, displaced fragments of a 
rock, especially on a hillside below an outcropping ledge or 
vein. 

flow - A lava flow. 

formation - A formally named stratigraphic unit consisting 
of a distinct, usually tabular body of rock that is mappable at 
the Earth's surface or traceable in the subsurface. 

fossil - Any remain, impression, or trace of a plant or animal 
from a former geologic age. 

fulgurite - An irregular, glassy, often tubular or rod-like 
structure or crust produced by the fusion of loose sand by 
lightning, and found esp. on mountain tops or in dune areas 
of deserts or lake shores. 



geomorphic - Pertaining to the form of the Earth or of its 
surface features. 

gneiss - A foliated rock formed by regional metamorphism, 
in which bands or layers of granular minerals alternate with 
bands or layers in which minerals having flaky or elongate 
prismatic habits predominate. 

granite - Aplutonic rock in which quartz consitiutes 10 to 50 
percent of the felsic components and in which the alkali 
feldspar/total feldspar ratio is generally restricted to the range 
of 65 to 90 percent. 

groin - A low, narrow jetty constructed of timber, stone, 
concrete, or steel, usually extending roughly perpendicular to 
the shoreline, designed to protect the shore from erosion by 
currents, tides, or waves, or to trap sand and littoral drift for 
the purpose of building or making a beach. 



H 



Holocene - The youngest and present epoch of the Quater- 
nary period, beginning approximately 10,000 years ago. 

hornblende - The most common mineral of the amphibole 
group. It is commonly black, dark green, or brown, and 
occurs as distinct monoclinic crystals or in columnar, fibrous , 
or granular forms. 

hydrothermal - Of or pertaining to hot water, to the action of 
hot water, or to the products of this action. 



I 



Ice Age - The Pleistocene Epoch, characterized by extensive 
continental and polar glaciation. 

ice rafting - The transportation of rock fragments of all sizes 
on or within icebergs, icefloes, or other forms of floating ice. 

ice sheet - A glacier of considerable thickness and more than 
19,000 sq mi in area, forming a continuous cover of ice and 



65 



snow over a land surface, spreading out in all directions and 
not confined by the underlying topography; a continental 
glacier. 

igneous - Formed by solidification from a molten or partially 
molten state. 

indurated - Said of a rock or soil hardened or consolidated 
by pressure, cementation, or heat. 

inlet - A small, narrow opening, recess, or indentation, or 
other entrance into a coastline or a shore of a lake or river, 
through which water penetrates into the land. 

intrusive - An adjective pertaining to intrusion, the process 
of emplacement of magma in pre-existing rock; magmatic 
activity; also the igneous rock mass so formed within the 
surrounding rock. 



from the wind; downwind. 

lens - A geological deposit bounded by converging surfaces, 
with at least one of them being curved, thick in the middle, 
and thinning out toward the edges. 

lignite - An imperfectly formed coal, usually dark-brown and 
commonly having a woody texture; brown coal. 

limestone - A sedimentary rock consisting predominantly of 
calcium carbonate, CaC0 3 . 

limonite - A yellow to brown, non-crystalline, hydrated iron 
oxide of varying composition. 

lithic - Pertaining to rock. 

longshore currents - An ocean current caused by the ap- 
proach of waves to a coast at an angle. 



jetty. - An engineering structure extending out from the shore 
into a body of water, designed to direct and confine the 
current or tide, to protect a harbor, to induce scouring, or to 
prevent shoaling of a navigable passage by littoral materials. 

joint - A surface of fracture or parting in a rock, without 
displacement; the surface is usually plane and often occurs 
with parallel joints to form part of a joint set. 

Jurassic - The middle period of the Mesozoic Era, lasting 
approximately from 195 to 141 million years ago. 



K 



kyanite - A blue or light-green mineral that occurs as long, 
thin, bladed crystals and crystalline aggregates in schist and 
gneiss. 



lagoon - A shallow stretch of seawater, such as a sound, 
channel, bay, or saltwater lake, near or communicating with 
the sea and partly or completely separated from it by a low, 
narrow, elongate strip of land, such as a reef, barrier island, 
sandbank, or spit. 

lahar - A mudflow composed chiefly of volcanic lastic mate- 
rials on the flank of a volcano. 

laminated - In thin layers. 

leeward - Said of the side or slope sheltered or located away 



M 



magma - Molten matter under the Earth's crust, from which 
igneous rock is formed by cooling. 

meander - One of a series of regular freely developing 
curves, bends, loops, turns, or windings in the course of a 
stream. 

Mesozoic - The middle of three eras of the Phanerozoic Eon, 
lasting from about 230 to 65 million years ago. 

metagraywacke - A metamorphosed dark gray firmly indu- 
rated coarse-grained sandstone that consists of poorly sorted 
angular to subangular grains of quartz and feldspar, with a 
variety of dark rock and mineral fragments embedded in a 
compact clayey matrix . 

metamorphic rock - A rock in which great heat or pressure 
has altered its original composition, structure, or texture. 

metamorphism - The mineral, chemical, and structural 
adjustment of rocks to exterior agencies such as deformation 
or a rise in temperature and pressure. 

metasedimentary - A metamorphosed sedimentary rock. 

metavolcanic - A metamorphosed volcanic rock. 

micaceous - Containing any of the mica, or sheet silicate 
minerals. 

Miocene - The older epoch of the Neogene Period, lasting 
from approximately 22.5 to 5 million years ago. 

mold - An impression made in the surrounding earth or rock 



66 



material by the exterior or interior of a fossil shell or other 
organic structure. 

monadnock - An upstanding rock, hill, or mountain rising 
conspicuously above the general level of a relatively flat 
plane in a temperate climate, representing an isolated 
remnant of a former erosion cycle in a mountain region that 
has been largely beveled to its base level. 

monazite - A yellow, brown, or reddish-brown mineral that 
is a principal ore of rare earths and thorium. 

mud flat - A relatively level area of clay and fine silt along 
a shore or around an island, alternately covered and uncov- 
ered by the tide, or covered by shallow water; a muddy tidal 
flat. 

mudstone - A clayey sedimentary rock of nearly uniform 
texture throughout, with little or no lamination. 

muscovite - A colorless to yellowish to pale brown mineral 
of the mica group. 

mylonite - A compact, chert- like rock without cleavage, but 
with a streaky or banded structure, formed by the extreme 
granulation and shearing of rocks that have been pulverized 
and rolled during overthrusting or intense metamorphism. 



O 



Oligocene - The youngest epoch of the Paleogene Period, 
lasting from approximately 37 to 22.5 million years ago. 

organic - Pertaining to or related to a compound containing 
carbon, especially as an essential component. 

outcrop - The part of a geologic formation which appears at 
the surface of the earth. 



remains in a water saturated environment, such as a bog or 
fen, and of persistently high moisture content (at least 75%). 
It is considered an early stage in the development of coal . 

period - A geologic time unit of rank between era and epoch. 

Permian - The last period of the Paleozoic era, thought to 
have covered a span of time between 280 and 225 million 
years ago. 

Phanerozoic - The current eon which started approximately 
570 million years ago, and consists of the Paleozoic, Meso- 
zoic and Cenozoic Eras. 

phyllite - A metamorphosed rock, intermediate in grade 
between slate and mica schist. Minute crystals of sericite and 
chlorite impart a silky sheen to the surfaces of cleavage. 

phyllonite - A rock that resembles phyllite but that is formed 
by mechanical degredation of initially coarser rocks. 

Piedmont - The low platform in the eastern United States 
extending eastward from the Appalachian and Blue Ridge 
Mountains to the Coastal Plain, and northward from Alabama 
to New Jersey. 

Pleistocene - The older of two epochs of the Quaternary 
Period, lasting approximately from 1.6 million to 10,000 
years ago. 

Pliocene - The younger of the two epochs of the Neogene 
Period, lasting from approximately 5 to 1 .6 million years ago. 

plutonic - Of deep igneous or magmatic origin. 

pocosin - A local term along the AUantic coastal plain south 
of Virginia for a swamp or marsh on a flat upland, bordering 
on or near the sea, in many cases enclosing knobs or hum- 
mocks. 



overwash - A mass of water representing the part of the 
uprush that runs over the berm crest (or other structure) and 
that does not flow directly back to the sea or lake. 



porphyry - An igneous rock of any composition that contains 
conspicuous crystals, larger than the surrounding crystals, 
surrounded by finer grained crystals. 



Paleocene - The oldest epoch of the Tertiary Period, lasting 
from approximately 65 to 55 million years ago. 

Paleogene -The Cenozoic Period which includes the Paleo- 
cene, Eocene and Oligocene epochs. 



pothole - A smooth, bowl-shaped or cylindrical hollow, 
generally deeper than wide, formed in the rocky bed of a 
stream by the grinding action of a stone or stones, or of coarse 
sediment, whirled around and kept in motion by the force of 
the stream current in a given spot. 

Precambrian - All geologic time prior to the beginning of 
the Cambrian Period. 



Paleozoic - The first era of the Phanerozoic Eon, lasting from 
approximately 570 to 230 million years ago. 

peat - An unconsolidated deposit of semicarbonized plant 



pyrite - A mineral, iron sulfide, FeS 2 , also called fool's gold, 
with the same composition as marcasite but with a different 
crystalline form. 



67 



Pr oterozoic - An eon in geologic time which started approxi- 
mately 2,500 million years ago and lasted until 570 million 
years ago. 

pyroclastic - Pertaining to clastic rock material formed by 
volcanic explosion or aerial expulsion from a volcanic vent. 



Q 



sandstone - A sedimentary rock composed chiefly of sand- 
sized quartz grains cemented by calcium carbonate, silica, or 
other materials. 

saprolite - A soft, earthy, typically clay-rich, thoroughly 
decomposed rock, formed in place by chemical weathering of 
igneous, metamorphic, or sedimentary rocks. Saprolite is 
characterized by the preservation of structures that were 
present in the unweathered rock. 



quartz - A hard, crystalline, vitreous mineral consisting of scarp - A cliff face produced by erosion or faulting, 
silicon dioxide, SiO, . 



quartzite - A granular metamorphic rock consisting essen- 
tially of quartz in interlocking grains. 

quartzose - Containing quartz. 

Quaternary - The third and present period of the Cenozoic 
Era, which began approximately 1.6 million years ago. 



R 



radiometric dating techniques - Any of several methods of 
determining the age of rocks or minerals by measuring the 
ratio of their radioactive atoms and their decay products. 

rapids - A swift, turbulent flow or current of water through 
an area of rock or outcrop that restricts the flow of water. 

regression - Seaward retreat of the shoreline through geo- 
logic time. 

relative age - A geologic age based on relative position in a 
sequence of rock units, or based on presumed position in a 
stratigraphic sequence. 

relief - The vertical difference in elevation between the 
hilltops or mountain summits and the lowlands or valleys 
of a given region. 

rhyolite - A group of extrusive igneous rocks, typically 
porphyritic and with flow structure, with phenocrysts of 
quartz and alkali feldspar in a glassy or very fine-grained 
groundmass. The extrusive equivalent of granite. 

rift valley - A valley that has developed along a long, narrow 
continental trough that is bounded by faults. 



schist - A strongly foliated metamorphic rock that can be 
easily split into thin flakes or slabs because of the well 
developed parallelism of more than 50% of the minerals 
present, particularly flat or elongate minerals, such as mica 
and hornblende. 

sediment - Solid fragmental material such as sand, gravel and 
clay, plus other transported fragments that settle to the bottom 
of a body of water. 

sedimentary rock - A rock formed from sediment. 

sedimentation - The process of accumulation of sediment. 

sericite - A white, fine-grained potassium mica occurring in 
small scales and flakes as an alteration product of various 
minerals; very similar to fine-grained muscovite. 

shale - A fissile sedimentary rock composed of laminated 
layers of clay-like, fine-grained sediments. 

shell limestone - A limestone containing the remains of 
shells or shell molds and casts. 

silica - Silicon dioxide, Si0 2 . 

sillimanite - Abrown, gray, pale-green, or white mineral that 
occurs in long, slender needlelike crystals. 

silicified - Cemented by or replaced with silica. 

siltstone - A sedimentary rock composed of silt-sized sedi- 
mentary particles. 

sinkhole - A natural depression in a land surface communi- 
cating with a subterranean passage, generally occurring in 
limestone regions and formed by dissolution or by collapse of 
a cavern roof. 



salt marsh - Hat, poorly drained land that is subject to 
periodic or occasional overflow by salt water, containing 
water that is brackish to strongly saline, and usually covered 
with a thick mat of grassy halophytic plants. 



spherulite - A rounded or spherical mass of needle-like 
crystals, commonly feldspar, radiating from a central point. 
Spherulites may range in size from microscopic to several 
centimeters in diameter. 

strata - Plural of "stratum." 



68 



stratigraphy - The science of rock strata. 

stratum - A layer of sedimentary rock, visually separable 
from other layers above and below. 

subgenus - A taxonomic rank below genus and above spe- 
cies. 



tuff - A general term for all unconsolidated rocks (pyroc las- 
tic) formed by volcanic explosion or aerial expulsion from a 
volcanic vent. 

tuff breccia - A pyroclastic rock consisting of more or less 
equal amounts of ash, and larger fragments. 



submarine - On the ocean floor. 



U 



surficial - Of, pertaining to, or occurring on the Earth's 
surface. 

swash zone - The sloping part of the beach that is alternately 
covered and uncovered by the uprush of waves, and where 
the longshore movement of water occurs in a zigzag manner. 



unconformity - A surface of erosion or non-deposition in the 
sedimentary rock record. 

ultramafic -An igneous rock composed chiefly of dark- 
colored iron- and magnesium-rich minerals. 



tectonism - A general term for all movement of the crust 
produced by tectonic processes, including the formation of 
ocean basins, continents, plateaus, and mountain ranges. 

tidal channel - A channel followed by tidal currents. 

tidal flat - An extensive, almost horizontal, marshy or barren 
area of unconsolidated sand and mud, which is alternately 
covered and uncovered by the tide. 

tidal delta - A delta formed at the mouth of a tidal inlet. 

transgression - Landward advance of the shore line through 
geologic time. 

Triassic - The oldest period of the Mesozoic Era, lasting from 
approximately 230 to 195 million years ago. 



vein - A thin sheet-like igneous intrusion into a fissure. 

volcanic - Pertaining to the activities, structures, or rock 
types of a volcano. 



W 



weathering - The physical disintegration and chemical de- 
composition of rock at the Earth's surface. 

weathering pit - A shallow depression on the flat or gently 
sloping summit of large exposures of granite or granitic 
rocks, attributed to strongly localized solvent action of im- 
pounded water. 



Triassic basin - A long, narrow trough filled with Triassic 
age sedimentary rocks. 



xenolith - A foreign inclusion in an igneous rock. 




69 



STATE LIBRARY OF NORTH CAROLINA 



3 3091 00661 1313 



DATE DUE 




G»Vl-ORD 



GEOLOGICAL SURVEY SECTION 



The Geological Survey Section shall by law "...make such examination, survey, and mapping 
of the geology, mineralogy, and topography of the state, including their industrial and economic 
utilization as it may consider necessary." 



In carrying out its duties under this law, the Section promotes the wise conservation and use 
of mineral resources by industry, commerce, agriculture, and governmental agencies for the general 
welfare of the citizens of North Carolina. 

The Section conducts a number of basic and applied research projects in environmental 
geology, mineral resource exploration, mineral statistics, and systematic geologic mapping. Serv- 
ices constitute a major portion of the Section's activities and include identifying rock and mineral 
samples submitted by the citizens of the State and providing consulting services and specially 
prepared reports to agencies that require geological information. 

The Geological Survey Section publishes results of research in a series of Bulletins, 
Economic Papers, Information Circulars, Educational Series, Geologic Maps, and Special Publica- 
tions. For a complete list of publications or more information about the Section please write: 
Geological Survey Section, P.O. Box 27687, Raleigh, North Carolina 2761 1. The telephone number 
is: (919) 733-2423. 



Jeffrey C. Reid 
Chief Geologist 



Front cover design by Denise Smith 




NORTH CAROLINA GEOLOGICAL SURVEY SECTION 
DIVISION OF LAND RESOURCES 

DEPARTMENT OF NATURAL RESOURCES 
AND COMMUNITY DEVELOPMENT